Date: Mon, 28 Nov 2016 18:07:26 +0000 From: Steven Hartland <killing@multiplay.co.uk> To: freebsd-stable@freebsd.org Subject: Re: Sandisk CloudSpeed Gen. II Eco Channel SSD vs ZFS = we're in hell Message-ID: <553eff7a-0cd5-eea9-4acd-4bc770fa1baf@multiplay.co.uk> In-Reply-To: <345ed411-1430-50f7-6887-5ac00d259fd9@norma.perm.ru> References: <345ed411-1430-50f7-6887-5ac00d259fd9@norma.perm.ru>
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Check your gstat with -dp so you also see deletes, it may be that your drives have a very slow TRIM. On 28/11/2016 17:54, Eugene M. Zheganin wrote: > Hi, > > recently we bough a bunch of "Sandisk CloudSpeed Gen. II Eco Channel" > disks (the model name by itself should already made me suspicious) for > using with zfs SAN on FreeBSD, we're plugged them into the LSI SAS3008 > and now we are experiencing the performance that I would call > "literally awful". I'm using already some of the zfs SANs on FreeBSD > with Intel/Samsung SSD drives, including the LSI SAS3008 controller, > but never saw anything like this (and yes, these are all SSDs): > > dT: 1.004s w: 1.000s > L(q) ops/s r/s kBps ms/r w/s kBps ms/w %busy Name > 75 472 78 367 104.4 12 1530 94.8 113.4| da0 > 75 475 81 482 79.2 12 1530 94.5 113.1| da1 > 69 490 96 626 106.9 12 1530 124.9 149.4| da2 > 75 400 72 382 51.5 10 1275 93.7 93.4| da3 > 0 0 0 0 0.0 0 0 0.0 0.0| da4 > 75 400 72 382 55.0 10 1275 93.9 93.7| da5 > 2 3975 3975 24020 0.3 0 0 0.0 21.0| da6 > 0 3967 3967 24144 0.3 0 0 0.0 21.4| da7 > 1 3929 3929 24259 0.3 0 0 0.0 21.6| da8 > 0 3998 3998 23933 0.3 0 0 0.0 21.2| da9 > 0 0 0 0 0.0 0 0 0.0 0.0| da10 > 0 4037 4037 23710 0.2 0 0 0.0 21.3| da11 > 0 0 0 0 0.0 0 0 0.0 0.0| da12 > 0 0 0 0 0.0 0 0 0.0 0.0| da13 > 0 0 0 0 0.0 0 0 0.0 0.0| da14 > 0 0 0 0 0.0 0 0 0.0 0.0| da15 > 0 0 0 0 0.0 0 0 0.0 0.0| da16 > > Disks are ogranized in the raidz1 pools (which is slower than the > raid1 or 10, but, considering the performance of SSDs, we got no > problems with Intel or Samsung drives), the controller is flashed with > last firmware available (identical controller with Samsung drives > performs just fine). Disks are 512e/4K drives, and "diskinfo > -v"/"camcontrol identify" both report that they have 4K > stripersize/physical sector. Pools are organized using dedicated > disks, so, considering all of the above, I don't see any possiblity to > explain this with the alignment errors. No errors are seen in the > dmesg. So, right at this time, I'm out of ideas. Everything point that > these Sandisk drives are the roort of the problem, but I don't see how > this is possible- according to the various benchmarks (taken, however, > with regular drives, not "Channel" ones, and so far I haven't figured > out what is the difference between "Channel" and non-"Channel" ones, > but they run different firmware branches) they have to be okay (or > seem so), just the ordinary SSD. > > If someone has the explanation of this awful performance, please let > me know. > > Thanks. > > Eugene. > > _______________________________________________ > freebsd-stable@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org"
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