Date: Thu, 5 Apr 2018 15:57:42 +0100 From: Steven Hartland <killing@multiplay.co.uk> To: freebsd-stable@freebsd.org Subject: Re: TRIM, iSCSI and %busy waves Message-ID: <2daf0677-3feb-6c4c-38d3-ed552f1a3cf0@multiplay.co.uk> In-Reply-To: <92b92a3d-3262-c006-ed5a-dc2f9f4a5cb9@zhegan.in> References: <92b92a3d-3262-c006-ed5a-dc2f9f4a5cb9@zhegan.in>
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You can indeed tune things here are the relevant sysctls: sysctl -a | grep trim |grep -v kstat vfs.zfs.trim.max_interval: 1 vfs.zfs.trim.timeout: 30 vfs.zfs.trim.txg_delay: 32 vfs.zfs.trim.enabled: 1 vfs.zfs.vdev.trim_max_pending: 10000 vfs.zfs.vdev.trim_max_active: 64 vfs.zfs.vdev.trim_min_active: 1 vfs.zfs.vdev.trim_on_init: 1 Regards Steve On 05/04/2018 15:08, Eugene M. Zheganin wrote: > Hi, > > I have a production iSCSI system (on zfs of course) with 15 ssd disks > and it's often suffering from TRIMs. > > Well, I know what TRIM is for, and I know it's a good thing, but > sometimes (actually often) I'm seeing my disks in gstat are > overwhelmed by the TRIM waves, this looks like a "wave" of 20K > 100%busy delete operations starting on first pool disk, then reaching > second, then third,... - at the time it reaches the 15th disk the > first one if freed from TRIM operations, and in 20-40 seconds this > wave begins again. > > I'm also having a couple of iSCSI issues that I'm dealing through > bounty with, so may be this is related somehow. Or may be not. Due to > some issues in iSCSI stack my system sometimes reboots, and then these > "waves" are stopped for some time. > > So, my question is - can I fine-tune TRIM operations ? So they don't > consume the whole disk at 100%. I see several sysctl oids, but they > aren't well-documented. > > P.S. This is 11.x, disks are Toshibas, and they are attached via LSI HBA. > > > 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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