From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nathan Dietsch Subject: Re: RAID5 crash and burn Date: Mon, 01 Nov 2004 00:54:20 +1100 Message-ID: <4184EE8C.2020408@ndietsch.com> References: <1430.63.204.219.3.1099198742.squirrel@63.204.219.3> <200410310518.i9V5ION22004@www.watkins-home.com> <1867.63.204.219.3.1099216777.squirrel@63.204.219.3> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1867.63.204.219.3.1099216777.squirrel@63.204.219.3> Sender: linux-raid-owner@vger.kernel.org To: coreyfro@coreyfro.com, linux-raid@vger.kernel.org List-Id: linux-raid.ids Hello Corey, coreyfro@coreyfro.com wrote: >Ahhhhhh... doesn't use the raidtab... nothing needs raidtab anymore... i >guess its time i got with the program... > >About swap failing, would there be much of a performence hit if i mirrored >swap? > > From what I read earlier in the thread, you already have a swap partition on software RAID5, so how would going to RAID1 hurt performance.? With swap on RAID5 -- unless you are paging very heavily (enough for a full-stripe write) -- it seems you would go into Read-Modify-Write anyway and this will hurt ... badly. Mirroring swap is a good idea to avoid crashes as Guy suggests. If you are seriously considering the performance implications of RAID1 vs RAID5 for swap, you are already done for performance wise. Personally I would not consider software RAID5 suitable for tasks which require performance. An exception would be for heavy I/O that causes full-stripe writes, in which case you would probably get a win out of the extra disks. I hope this helps. Kind Regards, Nathan Dietsch