Topic: RAID set up

[pssl]

Hi.

I'm upgrading my server.  I'm going from SME 6 to 7 on a new machine.  I'm setting up to perform the Upgrade process.  However, I'm struggling with a few things and need some guidance on RAID (for a start).  I think my system supports raid and maybe configured for it (I've got a question in an ASUS forum to find out how to find out.  The docs are sketchy and I couldn't see anything in the bois setup about enabling/disabling raid).

The story so far.  My system is an ASUS M4A78LT-M LE mb, installed with two 1T drives.  I've installed SME 7 which boots fine, as far as I can tell so far.  The next step is to perform the upgrade, but I have a concern.  During SME boot the message "No RAID disks" shows up, which surprised me.  My understanding is that, during installation, SME autodetects the two drives and sets up RAID automatically, unless hardware RAID is in place.  When I do fdisk -l, sda1 and sdb1 SYSTEM is "Linux RAID Autodetect".  I'm not clear on the significance of this, but I'm guessing that hardware raid is active.

I need help try to sort out what is going on.  Is my understanding correct?  Why does SME boot say "No RAID Disks"?  What does "Linux RAID Autodetect" mean?  If hardware raid is active, should I just go with that and ignore the software raid?

[Stefano]

The story so far.  My system is an ASUS M4A78LT-M LE mb, installed with two 1T drives.  I've installed SME 7 which boots fine, as far as I can tell so far.

so SME is installed properly and booting ok?

The next step is to perform the upgrade,

you forgot to tell us HOW are you trying to upgrade

[pssl]

Stefano

I'm sorry.  Should have been clearer.  I'm using the Upgrade Disk process (http://wiki.contribs.org/UpgradeDisk).  I haven't performed any of it yet.  I have a few things to clear up first, e.g., getting a backup of the disk from the old system and get clarification of this raid thing. 

I also forgot to mention that the old server was not a raid setup, but I've already clarified that this does not affect the Upgrade Disk process.

Yes, the fresh install of SME 7 seems to boot ok.  I'm able to log in as root and admin.

[janet]

pssl

The disk arrangement does not matter when doing backup and restore.

I think the message you see is "normal", before LVM is "instigated".

You obviously setup the new server OK, what RAID option did you select ?

Anyway just do
cat /proc/mdstat
and that should reveal some info re RAID configuration.

You can also login as admin and see the disk status in the Disk Maintenance menu.

Personally I would stick with software RAID1 as it us likely to be better than most motherboard "fake" RAID, unless you have a high end real RAID hardware card and a purpose specific need for it (good idea to keep a spare of the hardware card too in case of failure as without it you will not be able to get your system running again). Software RAID removes the dependency on specific hardware products, as the software RAID disks can be moved to any Linux/SME supported motherboard, in the event of a major hardware/motherboard failure.

[pssl]

Mary,

Thanks very much.  I can always count on you to provide good info.

Assuming your question "what RAID option did you select ?" refers to SME installation, I don't recall being given the option.  I was expecting at least a notice about raid being set up, but I do not recall seeing anything.  Is there an installation log that might be kicking around that I could look at?

Thanks for the guidance on s/w raid vs h/w raid--s/w raid it is then.  I cat'ed the mdstat which reported "md2: active raid1 sda2[0] sdb2[1]" and "md1: active raid1 sda1[0] sdb1[1]".  I got a reply from the motherboard forum on how to check the mb config for the SATA ports; I checked the bios which shows that the SATA ports are set to IDE and not RAID.  So, does the cat output mean that SME is configured for raid?

Also, when I do an fdisk -l | grep disk, I get the following 4 lines of output:

Code: [Select]

Disk /dev/md1 doesn't contain a valid partition table
Disk /dev/md2 doesn't contain a valid partition table
Disk /dev/dm-0 doesn't contain a valid partition table
Disk /dev/dm-1 doesn't contain a valid partition table
Is this something I should be concerned about?

[janet]

pssl

If you did not choose any particular RAID option or switch during install, and your motherboard BIOS was not set for RAID, then SME has automatically configured software RAID1 when it detected 2 installed drives. Refer to the SME server release notes re how various numbers of drives are automatically configured.

The cat /proc/mdstat output you quote is consistent with a fully functional software RAID1 setup.

The fdisk output you quote is also "normal" if you issue that command on a functional software RAID1 system.
Search these forums (& google) on md1 and RAID1 for a better understanding of what it all means.
Also look at output of
cat /var/log/dmesg |more

[pssl]

Thanks very much Mary.  I had searched the net for raid info, but, not having a full understanding of how raid works, I was not a 100% confident in my conclusion that all was normal.  I now am confident that I can move forward.  Thanks for your help.

[janet]

pssl

See
http://tldp.org/HOWTO/Software-RAID-HOWTO.html
and the currently maintained wiki link it refers to. Also read up on mdadm

[pssl]

Thanks Mary.  Will do.

[idp_qbn]

Mary's advice is always good - I have heeded it (and needed it) many times.

The easiest way to do a backup/restore from an old server to a new one is to use the AFFA contrib (http://wiki.contribs.org/Affa) on the new server.
AFFA does a periodic backup from OLD to NEW on a regular schedule AND it can be "risen" (as in 'rise up') to become a full server configured exactly as the old one was so it can take its place.
This means you have your old SEM6.x (OLDbox)and the new SME7.5.a + AFFA (AFFAbox) on the same network. If you OLDbox has 2 network cards, the AFFAbox will need two Network cards as well.

1) do an AFFA backup.
2) Stop OLDbox
3) Issue a "rise" command on AFFAbox
4) logon AFFAbox - it will now be called OLDbox - to check all is OK using "console" at the command prompt. Test the internet connection and check drive status.
5) connect your PCs to the new OLDbox - just start them up as usual if they automatically connect to drive shares etc.

It really is easy - and you have a rollback option in that you did not destroy the original OLDbox, it is still sitting there but switched off.

Good luck,
Ian

[janet]

idp_qbn

The easiest way to do a backup/restore from an old server to a new one is to use the AFFA contrib

Well Affa may be easy but not necessarily the easiest or quickest.

The UpgradeDisk method does not require a backup to be done, which can take a considerable time depending on the amount of data & other system factors.
Essentially it restores directly from the existing (mounted) old disk, to the new installation, so only a restore is required. This also means the contents of the old drive are unaltered, and the old system will still be fully operational if required (ie a fallback option).

One "issue" is that you have to physically remove the old drive from the old server and mount it on the new hardware temporarily, and some new motherboards may not support the older IDE drives, thus making IDE to SATA impossible for some situations using modern motherboards. SATA to SATA will obviously be OK.

The choice of upgrade/backup/restore method will really depend on the totality of a users circumstances.

[janet]

pssl

See also
http://wiki.contribs.org/Booting
and
http://wiki.contribs.org/Raid

[pssl]

Mary,

Again, thanks very much.  I figured that the Upgrade disk process didn't require a backup, but someone from a previous thread suggested it would be good idea, so I figured what can it hurt...and, yes, it is taking quite a bit of time, longer than I thought it would.

Fortunately, my new motherboard supports IDE drives, so once the backup is complete I'm good to go with the upgrade.

[janet]

pssl

It is NEVER a bad idea to do a backup, especially if you are about to "touch" (eg move & remount etc) the disk or make system changes etc.
If you only have the one disk coming from the sme6 server, then doing a backup of it is a good idea, actually you should have had a backup solution in place for it already, but it sounds like you did not ???
If your old system was a RAID1 array, then for the purposes of this upgrade exercise, you would have effectively had a backup on the other RAID disk, and in that case there would have been less need to do another external backup.

Anyway I agree that doing a backup is a good idea, better to be safe than sorry.

[CharlieBrady]

Mary's advice is always good

No, not always; just usually.