From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([69.77.167.62] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1K5kFn-0001bG-Dw for garchives@archives.gentoo.org; Mon, 09 Jun 2008 16:29:55 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 9FEF0E04AF; Mon, 9 Jun 2008 16:29:53 +0000 (UTC) Received: from iil.ie (mms2.iil.ie [217.78.9.37]) by pigeon.gentoo.org (Postfix) with ESMTP id 36429E04AF for ; Mon, 9 Jun 2008 16:29:53 +0000 (UTC) Received: from [192.168.1.14] by mms2.iil.ie (MDaemon PRO v9.6.5) with ESMTP id md50000996342.msg for ; Mon, 09 Jun 2008 17:29:53 +0100 X-Spam-Processed: mms2.iil.ie, Mon, 09 Jun 2008 17:29:53 +0100 (not processed: message from trusted or authenticated source) X-Authenticated-Sender: todd@iil.ie X-MDRemoteIP: 217.78.9.2 X-Return-Path: prvs=1046c543fa=todd@iil.ie X-Envelope-From: todd@iil.ie X-MDaemon-Deliver-To: gentoo-server@lists.gentoo.org Message-ID: <484D5A7B.1000601@iil.ie> Date: Mon, 09 Jun 2008 17:29:47 +0100 From: =?ISO-8859-1?Q?=22Todd_M=2E_H=E9bert=22?= Organization: Internet Ireland User-Agent: Thunderbird 2.0.0.14 (X11/20080505) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-server@lists.gentoo.org Reply-to: gentoo-server@lists.gentoo.org MIME-Version: 1.0 To: gentoo-server@lists.gentoo.org Subject: Re: [gentoo-server] what is the best filesystem for a server References: <200805210029.52385.oliver.schad@oschad.de> <4833982A.7010407@83864.com> <20080524121636.W29572@shell.bway.net> <41195fb10805241023v7829e298l9e124809bedf7aeb@mail.gmail.com> <23a5d5f00805241040h3563d04iaf38827ba4194bee@mail.gmail.com> <20080606091528.C63841@shell.bway.net> <484CF7C3.5030603@iil.ie> <41195fb10806090901s2afd0b2fgcabf45588b67aca6@mail.gmail.com> In-Reply-To: <41195fb10806090901s2afd0b2fgcabf45588b67aca6@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed X-MDAV-Processed: mms2.iil.ie, Mon, 09 Jun 2008 17:29:54 +0100 Content-Transfer-Encoding: quoted-printable X-Archives-Salt: e1df0e8e-7c0e-465a-8570-0bb493d5dc81 X-Archives-Hash: 3289bc3828d95bce28766f234c3b818c Whether the RAID is toast due to the loss of two drives depends on how ma= ny drives you're striping the data across and how many parity drives you = have. With RAID 5, if you have 9 drives you end up with one dedicated for parit= y, and the system should keep running with a loss of 2 drives without inc= ident. (provided that you replace the 2 affected drives before a third fa= ils.) I believe you can lose three drives out of 9 as long as it's not the pari= ty drive on RAID 5. On RAID 4, how many drives you can lose depends on whether you are runnin= g single or dual parity, and how many you have overall. You can run 8 da= ta drives plus dual parity.. in this configuration you should be able to = lose 2 data drives AND a parity drive (out of a 10-drive configuration) b= efore data becomes endangered. (or 3 data drives.) The major difference between 4 & 5 is being able to resize the RAID set o= n the fly. (adding drives to the RAID pool without having to completely = rebuild it.) The data centre that we're in tests their battery backup once each week, = and the diesel generators once a month. There are two completely discret= e power systems (from the cabling that our servers connect to, which are = always dual-powered, through the battery backups, and the generators. The= re is a spare battery backup system that can be manually shunted into pla= ce in the even that either of the primaries fails to perform... takes onl= y a few huge switches to change over, and all our networking kit is dupli= cated, so we can run without incident if we lose either of our power feed= s singly.) We have had zero downtime due to any faults in equipment owne= d by the data centre since opening in 1999... 3 other data centres within= 10 miles of here have had serious outages, including all-day outages, du= e to faults in their failover.. the guys we lease our space from really k= now what they're doing.) --Todd RijilV wrote: > 2008/6/9 "Todd M. H=E9bert" : >> We use RAID 1 on servers that are not file servers, RAID 4 or 5 on >> file-servers (depending on how much need for redundancy we have on a >=20 > Doesn't RAID 4 and 5 offer the same level of protection? I thought > the only difference was RAID4 had a dedicated parity device whereas > RAID5 stripes parity information across all devices. In either case, > loose two drives and the RAID is toast. >=20 >=20 >> We're in a data centre that isn't likely to have blackouts. (It can r= un on >> batteries for 6 hours, and has diesel generators with 48-hours worth o= f fuel >> on-site, as well as an emergency supply-chain for the diesel.) >=20 > I too have been in very very high profile very very nice data centers > with a jabillion hours of battery backup and even more of generator > power. One time someone hit the BIG RED BUTTON on the floor where > our gear was caged and presto - power was gone. Another time the city > cut the power mains to the building, and the generator that was > supposta supply half of our racks someone had left in "manual" mode as > apposed to automatic, thus taking out a fair number of our servers. I > think if you ask any sufficiently large group of people for horor > stories of power going out in a N+2 redundant power environmnet, > you'll get way more than you were looking for. >=20 >=20 >> I've not seen problems as described below on 3Ware cards... I believe = the >> configuration for each RAID is is backed-up on each disk in the RAID s= et. >> I've never had a problem with those. (I have seen a problem with ano= ther >=20 > I too have only ever had wonderful experiences with 3Ware cards under > Linux. I've not had one of their cards fail, but have had backplanes > fail and bad cables. Diagonosing and getting your vendor to admit to > a bad backplane generally requires more than one outtage :( Now LSI > cards on the otherhand have caused me some grief. >=20 >=20 >> XFS filesystems no all of the above, just for reference. >=20 > FWIW, always have run ext3, unless it was before ext3 was 'stable', > then it was ext2. >=20 -- Anything below this line is required by Irish law, and automatically i= nserted by the SMTP server -- ********************************************************************** "Private Confidential & Privileged" This Email and any files and attachments transmitted with it are confidential and/or privileged. They are intended solely for the use of the intended recipient. Any views and opinions expressed are those of the individual author/sender and are not necessarily shared or endorsed by Independent Newspapers (Ireland) Limited or any associated or related company. 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