ZFS on backup fileserver - RAM usage - FreeBSD

This is a discussion on ZFS on backup fileserver - RAM usage - FreeBSD ; I am planning to install new server for backups with 4x 1TB SATA II drives in RAIDZ. There will be about 20 separated filesystems from one zpool, few jails with ssh (scp/sftp), rsync and maybe FTP daemons, no other services ...

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Thread: ZFS on backup fileserver - RAM usage

  1. ZFS on backup fileserver - RAM usage

    I am planning to install new server for backups with 4x 1TB SATA II
    drives in RAIDZ. There will be about 20 separated filesystems from one
    zpool, few jails with ssh (scp/sftp), rsync and maybe FTP daemons, no
    other services with huge RAM utilization. As FreeBSD 7.1(-BETA) amd64
    still have some limits of kernel space memory, are there any benefits to
    put more then 2GB or 3GB in this server? Will it be more stabel or
    faster with for example 6GB of RAM? (I can buy it, RAM is really cheap
    in these days, but will it have some sense or is it vaste?)

    I am using this tuning on testing machine (with 2GB RAM):
    vm.kmem_size="1024M"
    vm.kmem_size_max="1024M"
    vfs.zfs.prefetch_disable="1"
    vfs.zfs.arc_min="16M"
    vfs.zfs.arc_max="64M"
    kern.maxvnodes="400000"

    (recommendations from http://wiki.freebsd.org/ZFSTuningGuide)

    Have somebody better results with another values?

    Miroslav Lachman
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  2. Re: ZFS on backup fileserver - RAM usage

    On Mon, Oct 13, 2008 at 01:44:32PM +0200, Miroslav Lachman wrote:
    > I am planning to install new server for backups with 4x 1TB SATA II
    > drives in RAIDZ. There will be about 20 separated filesystems from one
    > zpool, few jails with ssh (scp/sftp), rsync and maybe FTP daemons, no
    > other services with huge RAM utilization. As FreeBSD 7.1(-BETA) amd64
    > still have some limits of kernel space memory, are there any benefits to
    > put more then 2GB or 3GB in this server? Will it be more stabel or
    > faster with for example 6GB of RAM? (I can buy it, RAM is really cheap
    > in these days, but will it have some sense or is it vaste?)


    Adding more RAM will work just fine for userland programs, meaning they
    will be able to make use of the additional RAM. The kernel, with
    regards to kmap and kmem, however, will not. If you need that
    functionality, you'll have to run CURRENT.

    > I am using this tuning on testing machine (with 2GB RAM):
    > vm.kmem_size="1024M"
    > vm.kmem_size_max="1024M"
    > vfs.zfs.prefetch_disable="1"
    > vfs.zfs.arc_min="16M"
    > vfs.zfs.arc_max="64M"
    > kern.maxvnodes="400000"
    >
    > (recommendations from http://wiki.freebsd.org/ZFSTuningGuide)
    >
    > Have somebody better results with another values?


    The values look fine, but keep in mind that you still may encounter
    crashing with that kind of load (you're sticking a lot of stuff on one
    single box, all of which utilises ZFS heavily).

    You'll simply need to tune these as those situations arise.

    --
    | Jeremy Chadwick jdc at parodius.com |
    | Parodius Networking http://www.parodius.com/ |
    | UNIX Systems Administrator Mountain View, CA, USA |
    | Making life hard for others since 1977. PGP: 4BD6C0CB |

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  3. Re: ZFS on backup fileserver - RAM usage

    Thanks, Matt.

    I decide to correct these errors manually. Now rebuilding is in process. But
    I am afraid that I have missed something and it can corrupt my data in zfs
    pool. Lets check.

    __________________________________________
    > As I mentioned earlier, you want to sync to -HEAD as of the date of
    > the patch. Try something like this:
    >
    >
    > $ more /usr/local/etc/cvsup-head
    > *default host=cvsup8.FreeBSD.org
    > *default base=/var/db
    > *default prefix=/usr
    > *default release=cvs tag=.
    > *default delete use-rel-suffix
    > *default date=2008.08.13.00.00.00
    > *default compress
    > src-all
    >
    > On Oct 14, 2008, at 1:59 PM, Ruslan Kovtun wrote:
    > > I tried to apply this patch (zfs_20080727.patch) but I have found
    > > several
    > > errors (see below). Is this problem with patch or I need manualy
    > > apply these
    > > changes?
    > >
    > > Patching file cddl/contrib/opensolaris/lib/libzpool/common/sys/
    > > zfs_context.h
    > > using Plan A...
    > > Hunk #11 failed at 347.
    > >
    > > Patching file cddl/contrib/opensolaris/lib/libzpool/common/sys/
    > > zfs_context.h
    > > using Plan A...
    > > Hunk #11 failed at 347.
    > >
    > > Patching file sys/cddl/contrib/opensolaris/uts/common/fs/zfs/
    > > zfs_ctldir.c
    > > using Plan A...
    > > Hunk #26 failed at 1053.
    > >
    > > Patching file sys/cddl/contrib/opensolaris/uts/common/fs/zfs/
    > > zfs_replay.c
    > > using Plan A...
    > > Hunk #18 failed at 766.
    > >
    > > Patching file sys/cddl/contrib/opensolaris/uts/common/fs/zfs/
    > > zfs_vnops.c using
    > > Plan A...
    > > Hunk #82 failed at 3478.
    > >
    > > Patching file sys/cddl/contrib/opensolaris/uts/common/fs/zfs/
    > > zfs_znode.c using
    > > Plan A...
    > > Hunk #6 failed at 136.
    > > Hunk #13 failed at 560.
    > > Hunk #18 failed at 759.
    > > Hunk #20 failed at 877.
    > > Hunk #26 failed at 1336.
    > >
    > > Patching file sys/kern/kern_jail.c using Plan A...
    > > Hunk #1 failed at 34.
    > >
    > >
    > > __________________________________________________ __
    > >
    > >> On Oct 13, 2008, at 2:08 PM, Miroslav Lachman wrote:
    > >>> Matt Simerson wrote:
    > >>>> It all depends on your workload. If you work your backup serves
    > >>>> hard (as I do, backing up thousands of OS instances), you'll have
    > >>>> significant reliability problems using FreeBSD 7.1 and ZFS. After
    > >>>> a crash that corrupted my file systems, I have moved to 8-head
    > >>>> with Pawel's latest patch.
    > >>>> My backup servers have between 16 and 24 disks each. The ones with
    > >>>> 16GB of RAM crash far less frequently than my server that has only
    > >>>> 2GB. That one is getting upgraded soon.
    > >>>> Matt
    > >>>
    > >>> I am planning to backup about 10-15 servers (mainly webservers and
    > >>> few mailservers) and not expecting high load.
    > >>> Did 8-current with the latest ZFS patch fixed all stability
    > >>> problems?
    > >>>
    > >>> Thanks for suggestions to both of you.
    > >>>
    > >>> Miroslav Lachman
    > >>
    > >> No, there are still stability issues under heavy load. The are just
    > >> far less frequent under 8-current than under 7. I couldn't keep my
    > >> systems up for more than 2 days before switching to 8. Running 8-
    > >> head
    > >> was better, but so far the best available configuration is 8-head
    > >> with
    > >> "the patch" applied.
    > >>
    > >> Matt
    > >> _______________________________________________
    > >> freebsd-fs@freebsd.org mailing list
    > >> http://lists.freebsd.org/mailman/listinfo/freebsd-fs
    > >> To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org"

    > >
    > > --
    > > ________________
    > > Ruslan Kovtun
    > > mailto: yalur@mail.ru
    > > mob: +380503557878, +380919015095
    > > ICQ: 277696182

    >
    > _______________________________________________
    > freebsd-fs@freebsd.org mailing list
    > http://lists.freebsd.org/mailman/listinfo/freebsd-fs
    > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org"




    --
    ________________
    Ruslan Kovtun
    mailto: yalur@mail.ru
    mob: +380503557878, +380919015095
    ICQ: 277696182
    _______________________________________________
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    http://lists.freebsd.org/mailman/listinfo/freebsd-fs
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