Topic: Considering RAID5

[christian]

I've been running RAID1 for years now and when I moved to 7.0 I upgraded my HDDs at the same time again in RAID1.

Now I find myself running out of HDD space again (only a few months after upgrade from 120GB to 300GB). So instead of upgrading the HDDs again, I'm thinking to switch to RAID5 or possibly RAID6.

Have people generally been happy with the performance of the software RAID5? My guess is yes as for most of our Apps we are likely ethernet bound anyway.

Have you had reliability problems of say having more than one drive go at a time? I'm a little paranoid about this and am considering using the SME option of leaving one extra drive as spare. I assume this is a question asked at the console at installation time?

Once you start considering a spare disk then you naturally begin considering RAID6 and avoiding the risk during a rebuild.

Then again maybe I'm thinking too hard about this...

Christian

[uniqsys]

I've been running RAID1 for years now and when I moved to 7.0 I upgraded my HDDs at the same time again in RAID1.

Now I find myself running out of HDD space again (only a few months after upgrade from 120GB to 300GB). So instead of upgrading the HDDs again, I'm thinking to switch to RAID5 or possibly RAID6.

I don't think going to RAID5 will solve your capacity problem.  It sounds as if you need a SAN instead.

Have people generally been happy with the performance of the software RAID5? My guess is yes as for most of our Apps we are likely ethernet bound anyway.

Yes but RAID1 is cheaper and sufficient. A SAN is better.

Have you had reliability problems of say having more than one drive go at a time?

I have not but I have run only a handful of RAID5s -10-15 at most.  Never more than one drive failed at a time in any system and then rarely.

I'm a little paranoid about this...

You shouldn't be.

Then again maybe I'm thinking too hard about this...

Yes you are.  A SAN is the answer to the capacity problem, not RAID5 or 6, because RAID5&6 deal with insuring against disk failures not capacity.

I suggest you use a basic RAID1 for the SME and add a SAN mount that you point your users to for their data.  Search the forums, there must be something somewhere on using a SAN with SmallMediumEnterprise Server 7.x.

[pfloor]

Raid 5 will give you more capacity than raid 1.

2 (or 3 or 4) X 320gig RAID1 = 320gig total.

4 X 320gig RAID5 = (almost) 1TB total.

I run 4X320 SATA SW RAID5 on multiple servers.  It takes about 1 hour to sync them all up but after that they zip right along.

To do this you must have a board that has at least 4 (non-raid) SATA ports onboard.

I have done it with ATA but finding an ATA board with 4 onboard IDE channels is just about impossible these days.  Boards with 4+ sata ports is getting quite common but be careful and get one that runs all 4+ ports non-raid or it probably won't work.

[christian]

Thanks for the feedback. I was thinking of RAID5 primarily because I was looking for more capacity but wanted to maintain some level of redundancy (per pfloor's comment). Hence why thus far I have used RAID1. Problem I see now is getting a large enough disk to get capacity in RAID1.

This is for home and a SAN solution seemed like it would be quite expensive given its target market. I couldn't seem to find anything geared to the SOHO market that was more than glorified NAS. Netgear has an SC101 that is only Windows. Dlink has something that could link into Linux but doesn't seem to support virtualizing.

Contribs.org doesn't seem to have anyone who has done SAN from it either but I see I could theoretically use iSCSI or ATAoE.

Going SAN if i can get it to virtualize (i.e allow me to simply add more units to add capacity) would make it attractive.

Anyone using relatively inexpensive SAN technology that virtualizes?

[christian]

pfloor,

thanks for the input. I was going to use the two base IDEs on the main board plus use a Promise 133TX which has two more IDEs. My current 300GBs are each PATA thus I figured re-using my Promise card and adding two more PATAs would get me to 900GBs of capacity.

based on uniqsys's comments, I should be safe with a 4 disk RAID5 as well.

I'm also going to get my head around a SAN solution that links into the SME somehow. While I'm hesitant to go too far off standard (just seems to create more long term work) leveraging decent SAN technology sounds attractive.

It does need to link into one of my SMEs primarily because some of the services on it are actual users of most of this data.

[p-jones]

Anyone who has intgrated a SAN care to provide some more detail ? Make/Model, integretaion and authentication techniques/issues.

Maybe the moderator wants to move this to the general forum rather than hijacking this forum ?

Peter

[okepc]

Take a look at freenas

http://www.freenas.org/

I had a spare server and put in a bunch of spare disks 850 total gb.

Running like a charm

Supports raid configs too.

Dirk

[p-jones]

My experiences with FreeNAS and Sata Raid were not that great. Securing it like one would secure an iBay is a little challenging. That involves managing user permissions on two systems which is somewhat self defeating. Nonetheless, with a large drive and a small, cheap USB keydisk to boot from, it is a great system albeit with limitations as above.

[Stefano]

My experiences with FreeNAS and Sata Raid were not that great. Securing it like one would secure an iBay is a little challenging. That involves managing user permissions on two systems which is somewhat self defeating. Nonetheless, with a large drive and a small, cheap USB keydisk to boot from, it is a great system albeit with limitations as above.

AFAIR Freenas works also with MS domain authentication..

This said, I would use scsi controller/hds.. expensive but reliable..

eventually a external disk array: take a look on ebay

HTH

Stefano

[christian]

Take a look at freenas

http://www.freenas.org/

Dirk

Interesting. I was just about to ask about this in a new thread. The other two I had seen was OpenFiler and NASLite.

OpenFiler can take LDAP input so I suppose it could be slaved off an SME for some user data.

Any experience with any of these three or similar?

Also I've noticed in the forums that some people have been asking about this and how to tie in to SME7. However it would be interesting to see if anyone was successful with out going crazy and document at least a few pointers to get someone started.

Personally I could probably live with multiple user auth needs in my environment but what would be interesting is to see how you could replace either a part or all of the /home/e-smith/files directory with storage on a SAN or NAS.

[okepc]

The author of freenas is working on ldap and will be available in the next release as he stated.
Lots of other cool feature in freenas.

FreeNAS is a free NAS (Network-Attached Storage) server, supporting: CIFS (samba), FTP, NFS, AFP, RSYNC, iSCSI protocols, S.M.A.R.T., local user authentication, Software RAID (0,1,5) with a Full WEB configuration interface. FreeNAS takes less than 32MB once installed on Compact Flash, hard drive or USB key.

and Upnp
The project is highly active.

Dirk

[christian]

cool. Have you integrated into the SME with any of these protocols?

My off the cuff thought is FreeNAS may be more appropriate to my home centric needs. Although OpenFiler looks quite powerful (and arguably more mature).