From mboxrd@z Thu Jan 1 00:00:00 1970 From: "NeilBrown" Subject: Re: unbelievably bad performance: 2.6.27.37 and raid6 Date: Tue, 3 Nov 2009 16:36:33 +1100 Message-ID: <9e52db7bed791d8c8f5653b1958b1874.squirrel@neil.brown.name> References: <4AEEF29C.10309@tmr.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Jon Nelson Cc: LinuxRaid List-Id: linux-raid.ids On Tue, November 3, 2009 2:03 am, Jon Nelson wrote: > On Mon, Nov 2, 2009 at 8:54 AM, Bill Davidsen wrot= e: >> Jon Nelson wrote: >>> >>> I have a 4 disk raid6. The disks are individually capable of (at >>> least) 75MB/s on average. >>> The raid6 looks like this: >>> >>> md0 : active raid6 sda4[0] sdc4[5] sdd4[4] sdb4[6] >>> =A0 =A0 =A0613409536 blocks super 1.1 level 6, 64k chunk, algorithm= 2 [4/4] >>> [UUUU] >>> >>> The raid serves basically as an lvm physical volume. >>> >>> While rsyncing a file from an ext3 filesystem to a jfs filesystem, = I >>> am observing speeds in the 10-15MB/s range. >>> That seems really really slow. >>> >>> >> >> It is really slow, recent kernels seem to be unsuitable for use as l= arge >> file servers, as the performance is, as you described it, "unbelieva= bly >> bad." > > Yeah. I'm hoping that the 2.6.31.XX stable kernel series gets some of > these improvements, the .27 series has been not the most stable for m= e > either. 2.6.27.25 was the last rock-solid of the .27 series for me. I wouldn't get your hopes up... I did some limited testing of simple writes to ext2 and the current 32-pre kernel is noticably slower than .26 .27 .28 .29 .. (that is as far as I got with testing... I should write a script and leave it runni= ng overnight to get a broader picture). NeilBrown -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html