From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom De Mulder Subject: Re: Software RAID and TRIM Date: Mon, 18 Jul 2011 11:48:49 +0100 (BST) Message-ID: References: <4E235984.2070704@5t9.de> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Mon, 18 Jul 2011, David Brown wrote: First, I'd like to say that I've done more testing, and found that even after very prolonged, sustained heavy use, the (Intel 510) SSDs I partitioned 50/50 with half left unused didn't show any degradation in performance. That's after about a week of constant writing/erasing. > If your disks are reasonably full, then TRIM will not help much because the > garbage collection will be desperately trying to piece together small bits > into complete erase blocks, and your performance will drop through the floor. However, it won't drop as low as it would without TRIM in the same situation. But with a continuous heavy workload, even TRIM won't help, and over-provisioning is the way to go. Best, -- Tom De Mulder - Cambridge University Computing Service +44 1223 3 31843 - New Museums Site, Pembroke Street, Cambridge CB2 3QH -> 18/07/2011 : The Moon is Waning Gibbous (83% of Full)