Topic: Because Dar should not be considered for backups

[k_graham]

Latest 7.** SME all patches installed

Due to 1 of my mirrored Maxtor IDE drives going out of sync and as they are 5 years old I decided to upgrade - unfortunately it seems they can not be mirrored with a SATA drive so I need to do a backup and restore of some sort.  I purchased 2 Western Digital Black, Terabyte, 5 year warranted drives for the occasion at $100.00 each. By chance perusing Western Digitals warranty site I see they have black "Enterprise" drives for a bit more and at times a trade up from an old western digital drive - I would have gone Enterprise drives if I had known in addition to the 5 year warranty.

- Data most of which is in a IBAY is 114 Gigs. - I had a DAR backup so did try to use it - previously I had found I could not do a partial restore with DAR so I also make regular backups of Ibays using Winrar from www.rarlab.com/ which has always worked no matter the size, unfortunately the DAR restore feature doesn't bring up any window for restoring - it does not work on larger data sets.

So last night was spent reading Contribs on how to backup the configuration and sure enough there is a contrib there called http://wiki.contribs.org/Backup_server_config consequently I am currently implementing that - after which I will do a WinRar restore to the Ibay from the workstation. I know RAR was first used before DAR as a contrib, its too bad that was taken down as RAR has the advantage of being read using both Linux and Windows(WinRar) though WinRar is not free, it works on any size data I've thrown at it and also retains the files attributes.

Thanks again for the Backup Server Config info.

Thanks to whomever wrote up Backup server config.

Ken
Following signature is a copy of a batch file that allows one to backup

ibay  data
ibay Primary
ibay archive

to a workstation, you would need to change the server name fs to your server name and the ibays to your ibay names. in addition it adds a 1% recovery record in case of minor corruption and the first 2 lnes of each 3 delete the backup first so every time it is ran a new backup is made.

del d:\bu\WinrarEven-data.rar
del d:\bu\WinrarEven-data*.rar
C:\winrar\rar.exe a -u -as -tl -rr1%% -m5 -r -t -v2225000k -ilog d:\bu\Winrareven-data.rar \\fs\data\*.* 

del d:\bu\WinrarEven-FSprimaryWebSite.rar
del d:\bu\WinrarEven-FSprimaryWebSite*.rar
c:\winrar\rar.exe a -u -as -tl -rr1%% -m5 -r -t -v2225000k -ilog d:\bu\WinrarEven-FSprimaryWebSite.rar \\ss\Primary\*.*


del d:\bu\WinrarEven-Archive.rar
del d:\bu\WinrarEven-Archive*.rar
C:\winrar\rar.exe a -u -as -tl -rr1%% -m5 -r -t -v2225000k -ilog d:\bu\WinrarEven-Archive.rar \\fs\archive\*.* 

dir d:\bu\*.*
REM Did the data copy from a to Z & are their the same number of odd and even winrar's?
pause

[Stefano]

in this way you copy only the data.. you loose users and all settings..

if you don't feel confortable with SME's backup, try Affa

and I would add that your suggestion is potentially dangerous if followed by people with no experience..

do you still prefer rar/unrar? buy a license, install rpm on your server and create fragments/templates and share them with us..

[cactus]

IMHO you have not done enough research and are stating things that are not correct.
The build in dar backup solution, is capable of doing a selective restore. You can either use the command line or midnight commander to do so.
There is also a dar client for windows: http://sourceforge.net/projects/dar/files/dar/2.4.2/

[janet]

k_graham

You should look at
http://wiki.contribs.org/DAR2
note the section which tells you how to setup the midnight commander plugin
Type mc at the Linux prompt in case you are not aware.

You can easily look in and unpack a dar archive using mc, say to an ibay which is then accessible on a Windows computer.

The DAR2 contrib will allow you to make partial backup jobs of selected data on your server eg certain ibays only or whatever you specify.

I have never had trouble with large data sets, but some years back there were issues with certain web browsers ie Internet Explorer, so try using a good browser like Firefox.

[Stefano]

mary

as you can see here and here OP has already had the answers to his questions.

k_graham.. if you really want rar in place of dar on your server, you should:
- install rar from rpm
- create a file /etc/e-smith/events/actions/workstation-backup-rar with the right syntax.. you could use /etc/e-smith/events/actions/workstation-backup-dar as an example
- give

Code: [Select]

config setprop backupwk program rar
- test, test, test, test
- test, test, test, test

that's "all"

[k_graham]

mary

as you can see here and here OP has already had the answers to his questions.

k_graham.. if you really want rar in place of dar on your server, you should:
- install rar from rpm
- create a file /etc/e-smith/events/actions/workstation-backup-rar with the right syntax.. you could use /etc/e-smith/events/actions/workstation-backup-dar as an example
- give

Code: [Select]

config setprop backupwk program rar


I held off replying for a week to test some things - 1st dealing with Computers - the questions don't change - the answers over time do. A person with 5 Gigs of DAR data probably has no problem doing a selective restore but a person doing 100 plus gigs does have a problem.

I do not consider a backup that only a Linux user can restore from acceptable, if your system is like mine unable to do a partial restore using the browser and built in method then something else must be considered,  and I thank you for those suggestions.

As I mentioned the http://wiki.contribs.org/Backup_server_config did work as a method of providing a smaller amount of DAR data and then being able to restore with Winrar the Ibays.

 - the built in DAR backup solution was not capable of doing a selective restore on my system. I am not going to leave others to try using a Command line nor Midnight Commander as first they would have to move the dar data from Workstation backup to IBAy then go to Root then Midnight Commander.

Mary, I used your suggestion and did install DAR2 and then set up so it would not transfer the IBAYs this I think would let me restore the email and system after a catastophic event and would be current using same procedure mentioned in http://wiki.contribs.org/Backup_server_config but with benefit of being updated everyday with a weeks backups as well . Thankyou

Regards Ibay data, for the present I have decided to continue using WinRar from the Workstation - this has the advantage of offloading the compression to the my Workstation which is more powerful than my Server. Using Winrar I am able to create a  solid archive of 50 Gigs from 140 Gigs of data in 4 hours so easily overnight, and I can have a novice browse the archive to extract a file in 1 minute, 10 seconds if required.

While this is quite nice I do see some other interesting information in the contribs,

1. Shadow Copy which it seems would be even easier for a user to retrieve a previous version of a file, though maybe not a file they deleted, as if deleted how could they check for previous versions? Are any of you using it - anything of major concern?

2.Backup with Affa and Free DUP
I'm at a bit of a loss on this if I was to try duplicating at home possibly 2  work SME installations should I be trying to duplicate the running work systems  then make backups at home or creating backups at work and duplicate the backups to home? Should I be using Free Dup on the running work system or only the backups?

Free Dup sounds interesting - I do have a couple Windows 7 workstations using their built in Windows backup sending their C program drive to the server complete with a clone of their c drives so it sounds like it could considerably reduce program file storage. I don't feel this needs to be taken home as it probably would not be worth trying to restore to different hardware after a disaster so its excluded from my data backups.

While researching RAID and backups I also came across http://lime-technology.com/technology ,
it sounds like a interesting idea for cheap and reliable raid at cost of some speed, so far I guess I am as well off as I am still within mirroring of my harddrives and it only seems to be a benefit once one needs a minimum of 2 drives data,  Definitely limited in that it doesn't sit on a SME server - an awful lot of forum visits so others must find it useful. They seem to have a script for checking drives for use called PreClear -http://lime-technology.com/wiki/index.php?title=UnRAID_Add_Ons#Preclear_Disk , sounds like a good idea.

Maybe my title should be "Dar may not be suitable for all backups - where unable to do a selective restore on your hardware"

Thanks for your insights.

Ken

[cactus]

While this is quite nice I do see some other interesting information in the contribs,

1. Shadow Copy which it seems would be even easier for a user to retrieve a previous version of a file, though maybe not a file they deleted, as if deleted how could they check for previous versions? Are any of you using it - anything of major concern?

Regarding the inner workings of ShadowCopy and your backup demands I don't think this is the way to go. ShadowCopy keeps file copies of older files IIRC and I don't think you will have the storage space to accommodate those large files.

[k_graham]

Mary, I used your suggestion and did install DAR2 and then set up so it would not transfer the IBAYs this I think would let me restore the email and system after a catastophic event and would be current using same procedure mentioned in http://wiki.contribs.org/Backup_server_config but with benefit of being updated everyday with a weeks backups as well . Thankyou

Regards Ibay data, for the present I have decided to continue using WinRar from the Workstation - this has the advantage of offloading the compression to the my Workstation which is more powerful than my Server. Using Winrar I am able to create a  solid archive of 50 Gigs from 140 Gigs of data in 4 hours so easily overnight, and I can have a novice browse the archive to extract a file in 1 minute, 10 seconds if required.

Ken

Well, yesterday morning disaster struck - the server for some reason corrupted both drives a few minutes into the days work - so I have been trying to restore. I have a successful Dar2 backup so tried the following procedure after wasting the morning with fsck (after correcting the errors the Ibays were l not accessible)

1. Reinstall  new using 7.5 CD  Install Dar2

2. Copy the 70 GIG Backup from Workstation to external USB drive then try to do a install with external USB drive  (data not found - even with fat 32 sectors) Maybe my error was using the regular SME backup to try restore and it doesn't work for DAR2 backups.

3. Recreate a Backup in Dar2 using name of directory as stored on Workstation as data was still stored there as well.
    Login to webpanel from Workstation and have it do a Complete Restore
    "Success" showed immediately, which of course is not possible - I left it 8 hours assuming perhaps it meant the restore is happening?
    Did a Reconfigure from the Reboot/Shutdown part of WebPanel - waited several minutes with nothing happening, clicked Reconfigure again - only a warning shows that a Reconfigure is necessary. Did a Reboot from Webpanel as nothing appeared to be happening.

Rebooted - good part is User Names, Ibay names were in server control panel so something restored - bad news is I had set IBays to Prune (have the data within each Ibay backed up using WinRar)
So SME showed as if IBays were there but they were not and so no place to restore data to, I tried deleting an Ibay and restoring it but got a error during delete but it was no longer visible, then tried to restore and get an error saying it already exists - I then used Midnight Commander to manually add the empty Ibays (directories) and the deleted one now shows) Email doesn't accept the user passwords either and yet the email should have restored. (could be that its looking for complex passwords - ours are normal and should have restored as such)

4. Figured maybe the fact the Ibays had not been added before doing the Dar2 restore might have been part of the issue so have ran the restore using Dar2 a 2nd time but this time set for 1 day earlier, may loose 1 days email - except I automatically have the email forward a copy to a Google account so have it there. Immediately after seeing the word Success I told the system to do a Reconfigure - (nothing happening with the configure but was thinking it would do it as soon as its finished the restore ?

Will be looking at Affa after this.

Can only recommend people also print off each page of WebPanel - if DAR2 doesn't work I will be reinstalling new again, manually entering accounts and Ibays and restoring my data using my Winrar data backups and reading any old email in the gmail account used for backup. I'm just glad this happened near the weekend as it appears it may take all that time to fix.

So there is where I am now - hoping for some advise from those who have used DAR2 to understand where I am going wrong.

Thanks, Ken

[janet]

k_graham

Well where to begin !!
Your issues are because you have done selective backups, and now you want to do a full restore, and you do not fully understand what you are doing.
You seriously should reappraise your attitude to doing FULL backups using the built in dar method, it works well and is reliable.
You can configure it for one full & then daily incremental backups to keep backup times and stored data to a minimum.
If you MUST have WinRAR backups then do these seperately for users to selectively restore files from.

1. Reinstall  new using 7.5 CD  Install Dar2

To be sure, I assume you mean the DAR2 contrib.
From http://wiki.contribs.org/DAR2
did you read this part which details what to do to restore the DAR2 contrib configuration settings, so that a Restore will work easily & correctly.

"Manual restore of DAR2 configuration
It is possible to selectively restore the DAR2 configuration (backup job settings etc) from a full system backup. Firstly install the DAR2 contrib on a new server, which will of course have no backup jobs configured.
Then look at the backup file in the backup target location and find a file called db.zip. Extract the dar2 db file and copy it to /home/e-smith/db on the new server, to restore the previous DAR2 configuration."

I would suggest this is a more reliable way to do a full Restore using the DAR2 contrib on a newly installed SME OS.

Note the backup needs to be restored from the same location it was saved to, so if not already there, copy your DAR2 backup file(s) to the original location they were saved, as that is where DAR2 will be expecting them to be and looking for them.
The folder structure and names needs to be identical.

You would then need to restore your ibay data and so on that you have created using WinRAR backups.

You can always do a manual reconfigure
signal-event post-upgrade
signal-event reboot

Rebooted - good part is User Names, Ibay names were in server control panel so something restored - bad news is I had set IBays to Prune (have the data within each Ibay backed up using WinRar)

So it sounds like the restore did restore the system configuration and so on, but not ibays or ibay data as you had pruned that (and maybe not mysql webmail data)

It depends then what you specified as the prune path folder names, maybe the whole ibay structure is missing from the backup, BUT the SME database system configuration believes ibays are still in existence. So you have a system that is in contradiction with itself.

Look carefully at your prune statements to see what folder path has been pruned, although this will just confirm what I suspect.

So SME showed as if IBays were there but they were not and so no place to restore data to, I tried deleting an Ibay and restoring it but got a error during delete but it was no longer visible, then tried to restore and get an error saying it already exists - I then used Midnight Commander to manually add the empty Ibays (directories) and the deleted one now shows)

What you describe seems to match my conclusion of what is going on.

Creating new ibays with mc is very wrong, permissions, ownership & so on will all be wrong.

You should have deleted the ibays in SME server manager or failing that using these commands
http://wiki.contribs.org/SME_Server:Documentation:FAQ#Deletion_of_Users_Ibays_Groups
ie
signal-event ibay-delete ibayname
db accounts delete ibayname

The above will delete SME's knowledge of those ibays

Then recreate the ibays using server manager.
The ibays will then be there to manually restore the data from your WinRAR backups.

Email doesn't accept the user passwords either and yet the email should have restored. (could be that its looking for complex passwords - ours are normal and should have restored as such)

I cannot immediately explain why that might be so, perhaps you have pruned user data too ???, or maybe the mysql data has not been properly restored.
Webmail uses mysql db's.
Does your DAR2 backup include a mysql dump ? You can look in the backup file for a dump file(s) that is placed (IIRC) in
/home/e-smith/db/mysql

4. Figured maybe the fact the Ibays had not been added before doing the Dar2 restore might have been part of the issue so have ran the restore using Dar2 a 2nd time but this time set for 1 day earlier, may loose 1 days email - except I automatically have the email forward a copy to a Google account so have it there. Immediately after seeing the word Success I told the system to do a Reconfigure - (nothing happening with the configure but was thinking it would do it as soon as its finished the restore ?

Do not continue to use the current system, it is "corrupted".
Firstly check your backup has the mysql dump file.
If so, then re-install SME OS afresh, and install DAR2 contrib, add in the DAR2 configuration settings as described above, then delete and recreate the ibays (as per above), then manually restore the ibay data.

Will be looking at Affa after this.

I don't see that Affa will be any better if you continue to do partial backups. You will still have the same problems, complicated even further by the way Affa works (hard links & so on) and the need to install and configure it.

...hoping for some advise from those who have used DAR2 to understand where I am going wrong

Hope the above helps.
One piece of BIG advice
DO NOT RELY ON PARTIAL BACKUPS

Best you attach a big USB drive directly to the server, configure the built in e-smith-dar backup in server manager to do a workstation backup to local USB, configure for a full backup then daily incrementals for say 30days (your choice, it can be longer), and also have a second USB drive to rotate (swap) on a daily basis so that you have 2 reliable backups in the event that one should fail.

If you want RAR backups then run some seperate backups from workstations to workstations using WinRAR, users can restore individual files from those.

I have tried all the backup routines over the years and the above is what I have settled upon also.

[janet]

k_graham

One of your earlier/other posts commented/complained about inability to split the dar backup file into smaller sized parts.
You said WinRAR had an advantage in that it coudl split the backup file into smaller parts.
Well this can be done with the e-smith dar backup as per wiki here:
http://wiki.contribs.org/Backup_with_dar#Howto_set_the_backup_file_slice_size

[k_graham]

k_graham

Well where to begin !!
Your issues are because you have done selective backups, and now you want to do a full restore, and you do not fully understand what you are doing.

That was the issue -I had the backups but did not fully comprehend the best re-install method but with 20/20 hindsite can improve

You seriously should reappraise your attitude to doing FULL backups using the built in dar method, it works well and is reliable.

My concern was it appeared to time out when trying to do a individual file install and my server seemed to take too long with file compression enabled for the 100's of Gigs of data
 
You can configure it for one full & then daily incremental backups to keep backup times and stored data to a minimum.
If you MUST have WinRAR backups then do these seperately for users to selectively restore files from.

Daily incremental DAR backups would be deadly if the crash occurs during a backup as then the entire backup  from 7 to 30 days could be non existent

To be sure, I assume you mean the DAR2 contrib.

Yes

From http://wiki.contribs.org/DAR2
did you read this part which details what to do to restore the DAR2 contrib configuration settings, so that a Restore will work easily & correctly.

"Manual restore of DAR2 configuration
It is possible to selectively restore the DAR2 configuration (backup job settings etc) from a full system backup. Firstly install the DAR2 contrib on a new server, which will of course have no backup jobs configured.
Then look at the backup file in the backup target location and find a file called db.zip. Extract the dar2 db file and copy it to /home/e-smith/db on the new server, to restore the previous DAR2 configuration."

I would suggest this is a more reliable way to do a full Restore using the DAR2 contrib on a newly installed SME OS.

Note the backup needs to be restored from the same location it was saved to, so if not already there, copy your DAR2 backup file(s) to the original location they were saved, as that is where DAR2 will be expecting them to be and looking for them.
The folder structure and names needs to be identical.

While I read that I opted to simply create a full restore using the name and location of the backup - this is easier if one has printed out a page of their settings when creating the backup

You would then need to restore your ibay data and so on that you have created using WinRAR backups.

You can always do a manual reconfigure
signal-event post-upgrade
signal-event reboot


So it sounds like the restore did restore the system configuration and so on, but not ibays or ibay data as you had pruned that (and maybe not mysql webmail data)

It depends then what you specified as the prune path folder names, maybe the whole ibay structure is missing from the backup, BUT the SME database system configuration believes ibays are still in existence. So you have a system that is in contradiction with itself.

Look carefully at your prune statements to see what folder path has been pruned, although this will just confirm what I suspect.

What you describe seems to match my conclusion of what is going on.

Creating new ibays with mc is very wrong, permissions, ownership & so on will all be wrong.

You should have deleted the ibays in SME server manager or failing that using these commands
http://wiki.contribs.org/SME_Server:Documentation:FAQ#Deletion_of_Users_Ibays_Groups
ie
signal-event ibay-delete ibayname
db accounts delete ibayname

The above will delete SME's knowledge of those ibays

Then recreate the ibays using server manager.
The ibays will then be there to manually restore the data from your WinRAR backups.

I believe you are correct, one should not use MC (Midnight Commander) to create the directories (Ibays). If pruning directories I would now suggest after the install of SME server to install the Ibays from a printed list of Ibays kept with manual - I find one can print the web pages of the server panel with Microsoft Internet Explorer correctly where as FireFox prints blanks when right clicking page and telling to print. Then do the Dar2 Restore


I cannot immediately explain why that might be so, perhaps you have pruned user data too ???, or maybe the mysql data has not been properly restored.
Webmail uses mysql db's.
Does your DAR2 backup include a mysql dump ? You can look in the backup file for a dump file(s) that is placed (IIRC) in
/home/e-smith/db/mysql

I think the explanation is I had done a reconfigure but when considerable time went by with nothing happening I did a reboot and thus stopped the reconfigure from being complete - the 2nd time round I started the restore and as soon as the word "sucess" ocurred a few seconds later I went into the "Reboot or Shutdown" menu and entered a Reconfigure - then let both the restore complete after which it did a automatic reboot after the reconfigure. When I did it this way my email accounts were accessible passwords worked"


Do not continue to use the current system, it is "corrupted".
Firstly check your backup has the mysql dump file.
If so, then re-install SME OS afresh, and install DAR2 contrib, add in the DAR2 configuration settings as described above, then delete and recreate the ibays (as per above), then manually restore the ibay data.

re-installed SME OS afresh, and install DAR2 contrib, add in the DAR2 configuration settings as described above, create the ibays (as per above), run the Dar2 restore, - Reconfigure,  then manually restore the ibay data.


I don't see that Affa will be any better if you continue to do partial backups. You will still have the same problems, complicated even further by the way Affa works (hard links & so on) and the need to install and configure it.

For the time being I will not consider Affa

Hope the above helps.
One piece of BIG advice
DO NOT RELY ON PARTIAL BACKUPS

Best you attach a big USB drive directly to the server, configure the built in e-smith-dar backup in server manager to do a workstation backup to local USB, configure for a full backup then daily incrementals for say 30days (your choice, it can be longer), and also have a second USB drive to rotate (swap) on a daily basis so that you have 2 reliable backups in the event that one should fail.

If you want RAR backups then run some seperate backups from workstations to workstations using WinRAR, users can restore individual files from those.

I have tried all the backup routines over the years and the above is what I have settled upon also.

First please note I embedded some bold writing in above of what was done.

Best you attach a big USB drive directly to the server, configure the built in e-smith-dar backup in server manager to do a workstation backup to local USB, configure for a full backup then daily incrementals for say 30days (your choice, it can be longer), and also have a second USB drive to rotate (swap) on a daily basis so that you have 2 reliable backups in the event that one should fail.


Have you used the  built in e-smith-dar backup to do a full restore of more than 100 Gigabytes - it doesn't time out like a partial Restore?

I like the idea of a second USB drive to rotate but wouldn't that break the incremental backups, if the archive bit is being set to indicate the item is archived would not the 2nd USB drive miss the incremental data that was on the 1st USB drive?

Thanks,

Ken

[janet]

k_graham

Have you used the  built in e-smith-dar backup to do a full restore of more than 100 Gigabytes - it doesn't time out like a partial Restore?

I think my backup is about 300 - 400 Gb, and it restored OK some time ago.
It will take a long time though, many many hours depending on the speed of your equipment etc.
You have to be patient with big files or big data sets, and your equipment spec needs to be good eg plenty of RAM, modern fast CPU, good browser eg Firefox, high speed disks, high speed USB port and USB drives & so on.

You should really do some test backups and restores to sort out your problems rather than going to another system, and just continually saying that e-smith-dar does not work.
If it does not work as expected then there is potentially a bug & you should report it, or otherwise find out what it is in your system that is breaking the restores.

I like the idea of a second USB drive to rotate but wouldn't that break the incremental backups, if the archive bit is being set to indicate the item is archived would not the 2nd USB drive miss the incremental data that was on the 1st USB drive?

As I understand it, the incremental adds everything not already backed up on the target disk.
Each disk must initially have a full backup on it as the reference.
The system will do a full backup if there is no reference backup set (depending how you configure the backup).

Daily incremental DAR backups would be deadly if the crash occurs during a backup as then the entire backup  from 7 to 30 days could be non existent

Incorrect, the system will automatically pick up where it left off when the next scheduled backup occurs.
If an incremental backup is incomplete, then it will be added to on the next run.

I think the explanation is I had done a reconfigure but when considerable time went by with nothing happening I did a reboot and thus stopped the reconfigure from being complete - the 2nd time round I started the restore and as soon as the word "sucess" ocurred a few seconds later I went into the "Reboot or Shutdown" menu and entered a Reconfigure - then let both the restore complete after which it did a automatic reboot after the reconfigure. When I did it this way my email accounts were accessible passwords worked"

So a case of user error. Otherwise a bug that you choose not to report.

There is a long thread or two in the forums on the e-smith-dar backup, that discussed usage & design concepts, when the dar system was being implemented into SME.
It was originally a contrib.
Also I think there are some bug reports.
I strongly suggest you search for and read those threads as it will give you a much better understanding of the e-smith-dar system. It was a couple or a few years ago.

[k_graham]

k_graham

I think my backup is about 300 - 400 Gb, and it restored OK some time ago.
It will take a long time though, many many hours depending on the speed of your equipment etc.
You have to be patient with big files or big data sets, and your equipment spec needs to be good eg plenty of RAM, modern fast CPU, good browser eg Firefox, high speed disks, high speed USB port and USB drives & so on.

You should really do some test backups and restores to sort out your problems rather than going to another system, and just continually saying that e-smith-dar does not work.
If it does not work as expected then there is potentially a bug & you should report it, or otherwise find out what it is in your system that is breaking the restores.


As I understand it, the incremental adds everything not already backed up on the target disk.
Each disk must initially have a full backup on it as the reference.
The system will do a full backup if there is no reference backup set (depending how you configure the backup).

If it is an incremental backup then it will not create complete backups on each according to this
http://www.symantec.com/business/support/index?page=content&id=TECH7665
We need a Differential backup instead or if one has the time a Complete Backup on each USB drive each night.


Incorrect, the system will automatically pick up where it left off when the next scheduled backup occurs.
If an incremental backup is incomplete, then it will be added to on the next run.

So a case of user error. Otherwise a bug that you choose not to report.

I indicated a crash as in the file is damaged, without the index kept on the last segment of the file the file is no good thus up to 30 days is no good.

Again I added to the quote in bold, if the DAR backups are in fact incremental and not Differential then alternating USB drives is not the way to go.


Thanks,

Ken

[janet]

k_graham

Quoting symantec is irrelevant in this context.
The terminology used by e-smith-dar is full backup and incremental daily backup.

The e-smith-dar backup allows you to restore to any day that a backup was made either incremental or full, so your system can be restored to whatever day you want, not just the first or last.

If a file is damaged then your backup may be no good whichever system you use.
File failure problems are not just isolated to dar, WinRAR can have them too, and my recollection is with WinRAR it is a more catastrophoc result, as you indicate.

The whole point of having a second USB backup is to avert problems caused by a possibly faulty backup disk or file(s) ie one USB/backup may be faulty but the other USB/backup is still OK.

As I understand it, each USB backup disk set (full & daily incrementals) of a 2 disk rotating backup is independent of the other, and you can do a full restore to any day in the cycle from either disk.
IIRC there is a database that tracks the files backed up.

Please start listening to the advice given.

[k_graham]

k_graham

Quoting symantec is irrelevant in this context.
The terminology used by e-smith-dar is full backup and incremental daily backup.

The e-smith-dar backup allows you to restore to any day that a backup was made either incremental or full, so your system can be restored to whatever day you want, not just the first or last.

If a file is damaged then your backup may be no good whichever system you use.
File failure problems are not just isolated to dar, WinRAR can have them too, and my recollection is with WinRAR it is a more catastrophoc result, as you indicate.

The whole point of having a second USB backup is to avert problems caused by a possibly faulty backup disk or file(s) ie one USB/backup may be faulty but the other USB/backup is still OK.

As I understand it, each USB backup disk set (full & daily incrementals) of a 2 disk rotating backup is independent of the other, and you can do a full restore to any day in the cycle from either disk.
IIRC there is a database that tracks the files backed up.

Please start listening to the advice given.

Sorry Mary, I quoted the first outside party I could find via Google that explains why you are wrong.

quote
A Differential backup backs up only the selected files that have their archive bit set to ON but does not set the archive bit back to OFF. A Differential backup will back up all selected files that are new and changed since the last full backup. The advantage of a Differential comes at restore time; you'll need only the last full backup and the last differential to get a complete restore. In the case of restoring with Incremental backups, all the Incremental backups since the last full backup plus the last full backup would be necessary.

Avoiding incremental backups is likely why Darrel uses complete backups in DAR2. those you could swap drives nightly with.

I will defer to your opinion if DAR backups are Differential not incremental. I thinki we need a 3rd opinion on this one.

Thanks,

Ken Graham