From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.redhat.com (ext-mx07.extmail.prod.ext.phx2.redhat.com [10.5.110.31]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8428B5D762 for ; Fri, 20 Oct 2017 10:38:55 +0000 (UTC) Received: from smtp2.signet.nl (smtp2.signet.nl [83.96.147.103]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1C632C04B952 for ; Fri, 20 Oct 2017 10:38:52 +0000 (UTC) Received: from webmail.dds.nl (app2.dds.nl [81.21.136.118]) by smtp2.signet.nl (Postfix) with ESMTP id AD70140BCD52 for ; Fri, 20 Oct 2017 12:38:50 +0200 (CEST) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Date: Fri, 20 Oct 2017 10:38:50 +0000 From: Xen In-Reply-To: <62efc412-fd2b-5412-9de5-015dd8136bf2@member.fsf.org> References: <62efc412-fd2b-5412-9de5-015dd8136bf2@member.fsf.org> Message-ID: <133a1f046bbd53375d8c1230b2c1660f@xenhideout.nl> Subject: Re: [linux-lvm] cache on SSD makes system unresponsive Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: linux-lvm@redhat.com Oleg Cherkasov schreef op 20-10-2017 10:21: > On 19. okt. 2017 20:13, Xen wrote: >> >> The main cause was a way too slow SSD but at the same time... that >> sorta thing still shouldn't happen, locking up the entire system. >> >> I haven't had a chance to try again with a faster SSD. > > I have double checked with MegaRAID/CLI and all disks on that rig > (including SSD ones of course) are SAS 6Gb/s both devices and links. > My first thought about those SSDs was that those are slower than RAID5 > however it seems not the case. > > Could it be TRIMing issue because those are from 2012? You mean that the SATA version is too low to interleave TRIMs with data access? Because I think that was the case with my mSata SSD. I don't currently remember the sata version that allowed interleaving but that SSD didn't reach or have it. After trimming performance would go up greatly. So I don't know about SAS but it might be similar right.