Raid 5

[prasantamitra]

Can anyone experienced about Raid 5 problem in 100+ user deployment.

[DougWare]

I would like to see real results on this also.

Having tested many RAID devices and levels over the years (I was a contractor at a large three letter blue computer company), I know RAID5's shortcomings.

RAID5 is pretty fast for reads, but can have slow writes because each disk in the array must be updated (the data stripe and the checksum stripe). Personally, I would think that RAID5 on a hardware HBA should perform pretty well. After all, the bottleneck is the number of writes that have to occur, not the number of mailboxes on the server.

Just my 2 cents....

DougWare

[Chewie71]

We have several thousand users, probably 300-500 or so are active in any 10-15 minute period.

Per direction from Zimbra, we're running RAID10 on opt/zimbra/store, /opt/zimbra/index, and /opt/zimbra/db/data. Everything else is RAID5.

I would think in a situation where you only have a few hundred users, not all of whom will be active at any one time, RAID5 would be ok. If you need to scale much higher than that I would definitely look at RAID10.

With RAID5...the more disks(spindles) you throw at it the better your performance generally. So better to throw 15 smaller drives into it than 3 big drives. That's my understanding anyway.

Matt

[prasantamitra]

Thanks a lot for reply, currently I am running Raid 5 with 150+ user, and Thunderbird as email client. I haven't any option to ignore the Raid5 in my server. Plan to increase web client hope idle timeout helps me

[uxbod]

Also can be down to the type of storage DAS/NAS/SAN ?

[dijichi2]

With RAID5...the more disks(spindles) you throw at it the better your performance generally. So better to throw 15 smaller drives into it than 3 big drives. That's my understanding anyway.

Isn't it the opposite of that? Less spindles equals less simultaneous writes - particularly important if synchronous - and less parity calculations?

[Chewie71]

Isn't it the opposite of that? Less spindles equals less simultaneous writes - particularly important if synchronous - and less parity calculations?

Hmmm....maybe. I tried to do a quick Google search but didn't come up with the answer.

For sure...using a hardware RAID5, especially a SAN device with a HUGE cache, will reduce the performance bottleneck of RAID5. I would never use software RAID5 on anything in production. But...I'd still say go with Zimbra's recommendations and use RAID10 on your primary storage...unless you're running in a pretty small environment where disk performance is not going to be a problem.

Matt

[uxbod]

high volume writes equals RAID 10. loads of high speed (15k) spindles would be great