Date: Sun, 26 Aug 2012 13:13:50 -0700 From: Freddie Cash <fjwcash@gmail.com> To: Niki Hammler <mailinglists@nobaq.net> Cc: freebsd-fs@freebsd.org Subject: Re: zvol + raidz issue? Message-ID: <CAOjFWZ4Ep5ZONO%2B7UNqt36stFN_OXoMhK=83UwPpv51P8OTjfg@mail.gmail.com> In-Reply-To: <503A6F9F.7070801@nobaq.net> References: <503A6F9F.7070801@nobaq.net>
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(Sorry for top-post, sending from phone.) Please show the command-line used to create the zvol. Especially the recordsize option. When using zvols, you have to make sure to match the recordsize of the zvol to that of the filesystem used above it. Otherwise, performance will be atrocious. On Aug 26, 2012 11:50 AM, "Niki Hammler" <mailinglists@nobaq.net> wrote: > Hi, > > Given: new HP Proliant Microserver N40L (4 GB RAM) and 3x2TB SATA drives > (SAMSUNG HD204UI, ST32000542AS, WDC WD20EARX-00PASB0). > > Goal: RAIDz1 containg datasets and zvols to be exported via iSCSI. > > Issue: When I create a zvol on a RAIDz1 I get horrible performance (few > MB/s or less). > > First test: 500G zvol on a mirror (freshly created): > > # zpool list > NAME SIZE USED AVAIL CAP HEALTH ALTROOT > plvl1i0 1.81T 1.97G 1.81T 0% ONLINE /mnt > # zfs list > NAME USED AVAIL REFER MOUNTPOINT > plvl1i0 500G 1.30T 112K /mnt/plvl1i0 > plvl1i0/zvtest 500G 1.78T 1.97G - > # dd if=/dev/zero of=/dev/zvol/plvl1i0/zvtest bs=2048k count=1000 > 1000+0 records in > 1000+0 records out > 2097152000 bytes transferred in 17.318348 secs (121094230 bytes/sec) > # > > Corresponds to 115,48 MB/s which is good (similar results for a single > drive). > > Second test: 500G zvol on the 3x2TB raidz1 (freshly created): > > # dd if=/dev/zero of=/dev/zvol/plvl5i0/zvtest bs=2048k count=1000 > > 1000+0 records in > 1000+0 records out > 2097152000 bytes transferred in 700.126725 secs (2995389 bytes/sec) > # > > which is only 2,85 MB/s. > > Remark: Both pools are created with the force 4096 alignment option > (since I have 512 and 4096 drives mixed). > > Now is the point where you might say the problem is related to the > raidz1. But it is not: I created a 500G dataset in the same RAIDz pool > and copied about 100G data onto it with rsync+ssh. Result: about 28MB/s > end2end performance which is reasonable. > > Are there any issues with zvol + raidz1? Google resulted in empty result > set. > > I run a minimal FreeBSD 8.2 (FreeNAS): > > # uname -a > FreeBSD zetta 8.2-RELEASE-p9 FreeBSD 8.2-RELEASE-p9 #0: Thu Jul 19 > 12:39:10 PDT 2012 > root@build.ixsystems.com: > /build/home/jpaetzel/8.2.0/os-base/amd64/build/home/jpaetzel/8.2.0/FreeBSD/src/sys/FREENAS.amd64 > amd64 > > Regards, > Niki > > > PS: This is also posted on > http://forums.freenas.org/showthread.php?p=35590 > _______________________________________________ > 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" >
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