From owner-freebsd-fs@FreeBSD.ORG Mon Mar 10 17:32:24 2014 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id E742DCBE for ; Mon, 10 Mar 2014 17:32:24 +0000 (UTC) Received: from mail1.multiplay.co.uk (mail1.multiplay.co.uk [85.236.96.23]) (using TLSv1 with cipher RC4-MD5 (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 735047D9 for ; Mon, 10 Mar 2014 17:32:24 +0000 (UTC) Received: from r2d2 ([82.69.141.170]) by mail1.multiplay.co.uk (mail1.multiplay.co.uk [85.236.96.23]) (MDaemon PRO v10.0.4) with ESMTP id md50008558905.msg for ; Mon, 10 Mar 2014 17:32:15 +0000 X-Spam-Processed: mail1.multiplay.co.uk, Mon, 10 Mar 2014 17:32:15 +0000 (not processed: message from valid local sender) X-MDDKIM-Result: neutral (mail1.multiplay.co.uk) X-MDRemoteIP: 82.69.141.170 X-Return-Path: prvs=1146ddc565=killing@multiplay.co.uk X-Envelope-From: killing@multiplay.co.uk X-MDaemon-Deliver-To: freebsd-fs@freebsd.org Message-ID: From: "Steven Hartland" To: "Adrian Gschwend" , References: <531DF0DD.8070809@netlabs.org> Subject: Re: Reoccuring ZFS performance problems Date: Mon, 10 Mar 2014 17:31:56 -0000 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5931 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157 X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 10 Mar 2014 17:32:25 -0000 Looks like you may be out of IOP/s but just incase, are you using TRIM at all? sysctl -a |grep trim If you are what does "gstat -d" show? You also mention your using mysql, have you applied the standard tuning for mysql on ZFS? Regards Steve ----- Original Message ----- From: "Adrian Gschwend" To: Sent: Monday, March 10, 2014 5:05 PM Subject: Reoccuring ZFS performance problems > Hi group, > > (I have a lot of pastes in here, see http://pastebin.com/yjQnLryP for > this email in case the mail kills too long lines) > > On a regular base I run into some very weird ZFS performance issues on > my server. When it happens file IO is terribly slow and even a simple ls > can take a long time (worst case up to minutes). Everything which relies > on file IO is basically dead in this mode so even starting top or other > tools is a PITA. This stage can stay from minutes to hours and goes back > to normal after some random time. A reboot does not necessarily fix it, > often I'm back in exactly this stage after reboot. > > I do not see any patterns when it happens in my monitoring (munin), in > terms of when munin starts to time out because of it I do not see peaks > upfront in any of the system graphs I do. > > When I run 'top' in this mode I see many processes in one of these states: > > tx->tx > zfs > umtxn (mainly on mysql, which is unkillable in this mode) > uwait > > > Setup: > * FreeBSD 9.2-RELEASE-p3 in a KVM (SmartOS Solaris host, running ZFS itself) > * I'm using mfsbsd to do a ZFS only system > * No specific ZFS changes (I did play with some, see last part of email) > * There are 5 jails running > * I run various Apaches (PHP/SVN/TRAC etc), MySQL, LDAP daemon, a JVM > and some SIP servers (Freeswitch) > * Normal load is around 20-30% (2 cores) > * Swap is currently on 1% usage (4G available) > * I have 16GB of memory available, munin still shows around 1-2 GB as > free. It can be that the issue happens faster with less memory but I > cannot prove it either. > * Currently no dtrace enabled so can't get much further than standard > tools shipped with BSD > * zpool status does not report any failures > > The issues are not new, they first appeared while the system was still > running on real hardware (FBSD 8.x) and not within a KVM. Back then I > assumed I have a hardware problem but the problem reappeared on the > virtualized install. This install was basically a 1:1 zfs send copy plus > some bootloader hacking of the old system so exact same software levels. > I switched to a new install on 9.x and had the issue on every single > release there as well. I did not try 10.x yet. > > fstat | wc -l: > > 7068 > > (took forever to let it finish) > > gstat gives me: > > dT: 1.010s w: 1.000s > L(q) ops/s r/s kBps ms/r w/s kBps ms/w %busy Name > 10 575 1 0 0.2 574 653 17.8 100.4| vtbd0 > 0 0 0 0 0.0 0 0 0.0 0.0| > PART/vtbd0/vtbd0 > 0 0 0 0 0.0 0 0 0.0 0.0| vtbd0p1 > 0 0 0 0 0.0 0 0 0.0 0.0| vtbd0p2 > 10 575 1 0 0.3 574 653 18.0 100.4| vtbd0p3 > 0 0 0 0 0.0 0 0 0.0 0.0| > DEV/vtbd0/vtbd0 > 0 0 0 0 0.0 0 0 0.0 0.0| cd0 > 0 0 0 0 0.0 0 0 0.0 0.0| > DEV/vtbd0p1/vtbd0p1 > 0 0 0 0 0.0 0 0 0.0 0.0| > LABEL/vtbd0p1/vtbd0p1 > 0 0 0 0 0.0 0 0 0.0 0.0| > gptid/e402ecce-89ca-11e2-a867-3264262b9894 > 0 0 0 0 0.0 0 0 0.0 0.0| > DEV/vtbd0p2/vtbd0p2 > 0 0 0 0 0.0 0 0 0.0 0.0| > LABEL/vtbd0p2/vtbd0p2 > 0 0 0 0 0.0 0 0 0.0 0.0| > gptid/e4112d88-89ca-11e2-a867-3264262b9894 > 0 0 0 0 0.0 0 0 0.0 0.0| > DEV/vtbd0p3/vtbd0p3 > 0 0 0 0 0.0 0 0 0.0 0.0| > SWAP/swap/gptid/e4112d88-89ca-11e2-a867-3264262b9894 > 0 0 0 0 0.0 0 0 0.0 0.0| DEV/cd0/cd0 > 0 0 0 0 0.0 0 0 0.0 0.0| > DEV/gptid/e402ecce-89ca-11e2-a867-3264262b9894/gptid/e402ecce-89ca > -11e2-a867-3264262b9894 > 0 0 0 0 0.0 0 0 0.0 0.0| > DEV/gptid/e4112d88-89ca-11e2-a867-3264262b9894/gptid/e4112d88-89ca > -11e2-a867-3264262b9894 > 0 0 0 0 0.0 0 0 0.0 0.0| > ZFS::VDEV/zfs::vdev/vtbd0p3 > > ms/w changes a lot, highest I've seen right now was around 70 > > zfs iostat 2: > > capacity operations bandwidth > pool alloc free read write read write > ---------- ----- ----- ----- ----- ----- ----- > tank 173G 21.5G 3 56 30.9K 535K > tank 173G 21.5G 62 376 49.0K 1.22M > tank 173G 21.5G 46 340 84.3K 565K > tank 173G 21.5G 45 566 74.6K 800K > tank 173G 21.5G 32 222 92.0K 958K > tank 173G 21.5G 63 392 120K 1.10M > tank 173G 21.5G 16 286 14.2K 338K > tank 173G 21.5G 29 313 24.6K 831K > tank 173G 21.5G 0 289 0 445K > tank 173G 21.5G 27 244 32.6K 293K > tank 173G 21.5G 43 385 42.8K 477K > tank 173G 21.5G 31 329 15.7K 710K > tank 173G 21.5G 65 394 46.8K 1.50M > tank 173G 21.5G 80 320 127K 754K > tank 173G 21.5G 30 425 144K 1.09M > tank 173G 21.5G 13 399 25.9K 379K > tank 173G 21.5G 10 194 5.22K 162K > tank 173G 21.5G 18 311 45.5K 1.02M > tank 173G 21.5G 29 202 58.5K 344K > tank 173G 21.5G 32 375 108K 926K > > > on the host OS (SmartOS) zpool iostat 2 shows me (there is one other > FBSD box but there is almost no IO on this one): > > capacity operations bandwidth > pool alloc free read write read write > ---------- ----- ----- ----- ----- ----- ----- > zones 602G 230G 5 278 44.0K 2.42M > zones 602G 230G 2 154 19.9K 2.18M > zones 602G 230G 0 1.47K 0 10.3M > zones 602G 230G 0 128 0 1.44M > zones 602G 230G 0 270 0 2.61M > zones 602G 230G 0 1.39K 0 10.2M > zones 602G 230G 0 114 7.96K 2.10M > zones 602G 230G 0 979 7.96K 7.84M > > When the guest system is not in this state the writes are lower and I > don't see modes where I have 0 on reads. > > I was googling around about this topic forever and I do find people who > report similar issues. No one I've contacted found a real explanation > for it. Based on various guides I started adapting the basic config: > > cat /boot/loader.conf: > > vfs.zfs.zfetch.block_cap=64 > > # this one was horrible, bootup alone was dogslow > #vfs.zfs.write_limit_override=1048576 > > #vfs.zfs.txg.timeout="5" > > # so far good results? > vfs.zfs.prefetch_disable="1" > > First I thought disabling prefetch did solve the issue for a while. But > it looks like I was too optimistic with that one. However, ls feels > *much* faster when the system is happy since I disabled prefetch. > > I'm really totally lost on this one so I would appreciate hints about > how to debug that. > > I'm willing to test whatever it takes to figure out where this issue is. > > thanks > > Adrian > > > > > > > > _______________________________________________ > 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" > ================================================ This e.mail is private and confidential between Multiplay (UK) Ltd. and the person or entity to whom it is addressed. In the event of misdirection, the recipient is prohibited from using, copying, printing or otherwise disseminating it or any information contained in it. In the event of misdirection, illegible or incomplete transmission please telephone +44 845 868 1337 or return the E.mail to postmaster@multiplay.co.uk.