On 10/25/2013, 05:00 , centos-request@centos.org wrote:

We are a CentOS shop, and have the lucky, fortunate problem of having ever-increasing amounts of data to manage. EXT3/4 becomes tough to manage when you start climbing, especially when you have to upgrade, so we're contemplating switching to ZFS.

As of last spring, it appears that ZFS On Linuxhttp://zfsonlinux.org/ calls itself production ready despite a version number of 0.6.2, and being acknowledged as unstable on 32 bit systems.

However, given the need to do backups, zfs send sounds like a godsend over rsync which is running into scaling problems of its own. (EG: Nightly backups are being threatened by the possibility of taking over 24 hours per backup)

Was wondering if anybody here could weigh in with real-life experience? Performance/scalability?

-Ben

FWIW, I manage a small IT shop with a redundant pair of ZFS file servers running the zfsonlinux.org package on 64-bit ScientificLinux-6 platforms. CentOS-6 would work just as well. Installing it with yum couldn't be simpler, but configuring it takes a bit of reading and experimentation. I reserved a bit more than 1GByte of RAM for each TByte of disk.

One machine (20 useable TBytes in raid-z3) is the SMB server for all of the clients, and the other machine (identically configured) sits in the background acting as a hot spare. Users tell me that performance is quite good.

After about 2 months of testing, there have been no problems whatsoever, although I'll admit the servers do not operate under much stress. There is a cron job on each machine that does a scrub every Sunday.

The old ext4 primary file servers have been shut down and the ZFS boxes put into production, although one of the old ext4 servers will remain rsync'd to the new machines for a few more months (just in case).

The new servers have the zfsonlinux repositories configured for manual updates, but the two machines tend to be left alone unless there are important security updates or new features I need.

To keep the two servers in sync I use 'lsyncd' which is essentially a front-end for rsync that cuts down thrashing and overhead dramatically by excluding the full filesystem scan and using inotify to figure out what to sync. This allows almost-real-time syncing of the backup machine. (BTW, you need to crank the resources for inotify waaaaay up for large filesystems with a couple million files.)

So far, so good. I still have a *lot* to learn about ZFS and its feature set, but for now it's doing the job very nicely. I don't miss the long ext4 periodic fsck's one bit :-)

YMMV, of course, Chuck