From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: high throughput storage server? Date: Wed, 16 Feb 2011 08:41:36 +1100 Message-ID: <20110216084136.1c7efa28@notabene.brown> References: <20110215044434.GA9186@septictank.raw-sewage.fake> <4D5A98BF.3030704@gmail.com> <20110216073756.4c0291eb@notabene.brown> <4D5AE669.10107@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4D5AE669.10107@gmail.com> Sender: linux-raid-owner@vger.kernel.org To: Joe Landman Cc: Matt Garman , Doug Dumitru , Mdadm List-Id: linux-raid.ids On Tue, 15 Feb 2011 15:47:37 -0500 Joe Landman wrote: > On 02/15/2011 03:37 PM, NeilBrown wrote: > > On Tue, 15 Feb 2011 10:16:15 -0500 Joe Landman wrote: > > > >> As a tie in to the Linux RAID list, we use md raid for our OS drives > >> (SSD pairs), and other utility functions within the unit, as well as > >> striping over our hardware accelerated RAIDs. We would like to use > >> non-power of two chunk sizes, but haven't delved into the code as much > >> as we'd like to see if we can make this work. > >> > > > > md/raid0 (striping) currently supports non-power-of-two chunk sizes, though > > it is a relatively recent addition. > > (raid4/5/6 doesn't). > > Cool! We need to start playing with this ... > > Which kernels have the support? It was enabled by commit fbb704efb784e2c8418e34dc3013af76bdd58101 so $ git name-rev fbb704efb784e2c8418e34dc3013af76bdd58101 fbb704efb784e2c8418e34dc3013af76bdd58101 tags/v2.6.31-rc1~143^2~18 2.6.31 has this support. However I note that mdadm still checks that the chunk size is a power of two: if (chunk < 8 || ((chunk-1)&chunk)) { I should fix that... NeilBrown > > -- > Joe > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html