Date: Tue, 16 Feb 2010 00:45:38 +0100 From: Miroslav Lachman <000.fbsd@quip.cz> To: freebsd-scsi@freebsd.org Cc: ivoras@freebsd.org Subject: performance tuning of iSCSI and Dell MD3000i / gjournal problem Message-ID: <4B79DCA2.1070005@quip.cz> References: 4B5F1553.4070709@quip.cz
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I am sorry for my late reply, I am not subscribed to this list and I was busy by my other work. Please CC me next time. >> >> Just a note, I am still having performance problems with iSCSI and Dell >> MD3000i. >> I tried it with ZFS, but writing performance was even worse - about >> 3-5MB/s! Copying 33GB from local UFS partition do iSCSI ZFS partition >> takes almost 5 hours: > > You've written a lot of information here. Firstly, is your problem > related to iSCSI performance, ZFS performance or UFS performance? As it > looks to me, you are mostly complaining about iSCSI performance, right? I am complaining about iSCSI performance in general. I think it should give some better results on gigabit link with underlying RAID5 of 4 SATA 7200rpm drives. The performance is much below one physical SATA drive. Then I use 3 different setups to test if it is just iSCSI problem, or UFS+SU. UFS+SU have much lower write performance than UFS+Gjournal, but gjournal doesn't work well with iSCSI at boot time. And ZFS on iSCSI is the worst case with 5MB/s write performance! (I have much better experiences with ZFS on RAIDZ pool of 4 SATA drives) The mentioned iSCSI storage (Dell MD3000i) is now in production serving about 200Mbits (350Mbits in peaks) through Lighttpd, using UFS+SU. It is used almost read only, so write performance doesn't matter at this time, but if there will be any disaster and I will need to restore backups, it will take more than 2 days to copy 1TB of data! Miroslav Lachman
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