Re: Do you do HSM?

[Matt Mencel <MR-Mencel@wiu.edu>]

Yup...responses inline...


----- "Xueshan Feng" <sfeng@stanford.edu> wrote:

> I am interested to know the real world experience of Zimbra HSM
> deployment. I found some archived articles on this mailing list from
> 2008 about using HSM, but things have changed so much since and I
> believe there are must be more customers actively using HSM now. 
> 
> There is a good wiki page http://wiki.zimbra.com/wiki/Ajcody-HSM-Notes
> that covers various implementation considerations and setup, but I'd
> like to know anyone who uses HSM in their production environment has
> lessons, concerns and 'howtos' to share. Here are my specific
> questions (with some answers for our university, when applicable). All
> in all, does it worth to trade potential system performance impact
> with cheaper storage? 
> 
> 1. How many user accounts per mailbox server
> 
> We have 9 servers, each has about 5000 accounts.

3000-4000 active accounts per server...5 mailbox servers.  8000+ if you count accounts that are inactive or have very little activity.
 
> 
> 2. How much mailbox quota per account 
> 
> 1GB  by default. Additional quota can be purchased. Mailstore disk
> usage is around 1.5TB on each server. 
>

1GB for students and 2GB for faculty/staff.  When they reach their quota they can get a bump by asking for it if they want.
 
> 3. Storage architecture: do you use different storage for zimbra root
> /opt/zibmra, and zimbra backup /opt/zimbra? 
> 
> We have /opt/zimbra  (database, redolog, logs) on fast disk connected
> through fiber channel to SAN disks. /opt/zimbra/backup is mounted as
> NFS partition through Ethernet connection to NetApp server, slower
> disks.
>
> If you use HSM, what kind of secondary storage do you use? Do you use
> NFS mounted file system for secondary volume?   
> 

50G   28G   22G  57% /opt/zimbra-cluster/mountpoints/zimbra4.wiu.edu/store
795G  519G  261G  67% /opt/zimbra-cluster/mountpoints/zimbra4.wiu.edu/hsm
985G  750G  195G  80% /opt/zimbra-cluster/mountpoints/zimbra4.wiu.edu/backup

Everything is fiber connected to a SUN SAN. HSM and BACKUP are SATA disk with RAID5.  Everything else is FC disk with RAID10.


> 4. Do you have dedicated network connection  to the HSM storage?
> 
> We are looking into HSM, but our servers have only one Ethernet
> interface, and we may need to share that connection used by the backup
> volume. 
> 
> Will it be a performance problem if both backup and the secondary HSM
> volume share the same network connection?
> 

Our HSM and BACKUP are directly attached SAN disk so this is not an issue.

> 5. Impact with backups
> 
> Our current backups (NFS mounted partition) takes more than 10 hours
> already, even we use 7-group backup policy. Offering more storage
> obviously will make the backup runs longer. If HSM process has to run
> at off-peak hour and  over-ldaps with the backup process,  how bad it
> can be?  Do you use higher number of auto-group policy, like 14 or 31
> auto-groupping? 
> 

We autogroup using 7 days.  We also do no-zip backups which improves backup time.  If you are putting this data off somewhere else for DR purposes though you might run into problems if you don't zip.  Too many files for the backup software to process easily.

> 6. Impact to server
> 
> Obviously moving data from primary disk to secondary disk will have
> impact to server performance. Do you let your HSM process run
> continuously? Is the performance impact end user email experience
> during the business hours? 
>

We run it once a day in the wee hours of the morning.  No impact.
 
> 7. What HSM Age do you use? If you adjusted it from the default 30
> days, why? 
>

10 days.  Like someone else said...we try to keep our primary store below about 70-80% utilization.
 
> 8. When you initially turn on HSM, how long did it take for a complete
> run? How long does it take after the intial run? 
>

I think we've had it on since we started using Zimbra several years ago so I don't remember.  The daily HSMs do not take very long at all.

Of course...we're a little different then a lot of sites in that we use fiber connected storage for our HSM and BACKUP.  We don't notice any performance issues during the HSM process.  It does not seem to interfere at all with backup performance even though they sometimes run concurrently.  And users don't notice that the email or document they just pulled up came off of HSM or STORE.  There is so little difference that I don't think it's noticeable in the web UI.

Using iSCSI or NFS connected storage over ethernet may be a different story....but there's plenty of others here who know and use it successfully that way.

Matt

 
> Thanks!
> 
> Xueshan
> 
> -- 
> 
> Xueshan Feng <sfeng@stanford.edu>
> Technical Lead, IT Services, Stanford University
> 
> -- 
> 
> Xueshan Feng <sfeng@stanford.edu>
> Technical Lead, IT Services, Stanford University
> 
> -- 
> 
> Xueshan Feng <sfeng@stanford.edu>
> Technical Lead, IT Services, Stanford University
> 
> -- 
> 
> Xueshan Feng <sfeng@stanford.edu>
> Technical Lead, IT Services, Stanford University
> 
> -- 
> 
> Xueshan Feng <sfeng@stanford.edu>
> Technical Lead, IT Services, Stanford University
> 
> -- 
> 
> Xueshan Feng <sfeng@stanford.edu>
> Technical Lead, IT Services, Stanford University