From mboxrd@z Thu Jan 1 00:00:00 1970 From: klink@clouddancer.com (Colonel) Subject: (unknown) Date: Tue, 4 Jun 2002 18:54:52 -0700 (PDT) Sender: linux-raid-owner@vger.kernel.org Message-ID: <20020605015452.70D1D8347@phoenix.clouddancer.com> Return-path: To: linux-raid@vger.kernel.org, pegasus@telemach.net List-Id: linux-raid.ids From: Colonel To: pegasus@telemach.net CC: linux-raid@vger.kernel.org In-reply-to: <20020604235518.2cb7d7d7.pegasus@telemach.net> (message from Jure Pecar on Tue, 4 Jun 2002 23:55:18 +0200) Subject: Re: Reply-to: klink@clouddancer.com References: <20020604154712.AD48D8347@phoenix.clouddancer.com> <20020604235518.2cb7d7d7.pegasus@telemach.net> Date: Tue, 4 Jun 2002 23:55:18 +0200 From: Jure Pecar On Tue, 4 Jun 2002 08:47:12 -0700 (PDT) klink@clouddancer.com (Colonel) wrote: > > True, I think that the point is that of the 5 possible 2 disk > failures, 2 of them (in striped mirrors, not mirrored stripes) kill > the array. For RAID5, all of them kill the array. But the fancy RAID > setups are for _large_ arrays, not 4 disks, unless you are after the > small write speed improvement (as I am). going offtopic here ... what kind of raid setup is the best for write intensive load like mail queues & co? define "best" For sequential writes, RAID10 is considered 'best'. However, there are two ways to make "10", one has far better reliability -- which is best for some configurations, the striped mirrors. YMMV To truely answer your question requires knowing how many drives, detailed load and bandwidth info, economics and politics. > Plus any raid metadevice made of metadevices cannot autostart, which > means tinkering during startup, which is only worth it for those large > drive arrays. hm? it does for me. probalby the redhat's rc.sysinit does the right thing ... If you can run one on / (the root partition), then it autostarted. If it's on /usr, then it was manually started (if it's striped mirrors) to my knowledge. On the other hand, you may have mirrored stripes -- which potentially do autostart (I vaguely remember this discussion many moons ago, when M.Ingo was introducing the current raid, but I wanted raid 5 ...). For myself, I grew disatisfied with the disk usage in RAID5. All drive 'lights' were on too often. Now, it's quieter, slightly faster, less blinky lights and smaller.