From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <5426BF5C.9090301@kernel.dk> Date: Sat, 27 Sep 2014 07:45:00 -0600 From: Jens Axboe MIME-Version: 1.0 Subject: Re: dedupe and replay References: <5425B9B7.2080003@kernel.dk> <5425C0C7.8080303@kernel.dk> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit To: Alket Memushaj Cc: fio@vger.kernel.org List-ID: On 09/27/2014 05:19 AM, Alket Memushaj wrote: > thanks for the quick response - but unfortunately this patch does not > seem to have changed the result. I managed to get a 1.4:1 dedupe when > setting dedupe_percentage to 99%. The test rig I have is like this: an > array w/ inline dedupe @ 4K and I am the only user on it - I have a > single machine mounting a single lun from the array (the whole space > in the array is assigned to this lun). The synthetic test at > dedupe_percentage=80 results in a 4:1 dedupe ratio from the array. The > replay at 80% comes out as undedupable (ratio = 1.0:1) even with the > latest patch. The replay generates about 1.7 million I/Os. ~1 million > are 4K, 80 thousand are 8K, 70 thousand are 32K, etc... there's a > decent number of I/O that is not a multiple of 4K, but the vast > majority of the I/O is a multiple of 4K. The offset for each I/O is 4K > aligned in the vast majority of I/Os. (please don't top post) I'll try with a trace replay here. If you can, would be nice to get your trace. -- Jens Axboe