From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: mdadm on huge raid sets Date: Wed, 23 May 2007 08:12:09 +1000 Message-ID: <18003.27321.583707.520299@notabene.brown> References: <465349B9.3030702@soe.ucsc.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: message from Erich Weiler on Tuesday May 22 Sender: linux-raid-owner@vger.kernel.org To: Erich Weiler Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Tuesday May 22, weiler@soe.ucsc.edu wrote: > Greetings all- > > Quick question. We've got one of these new Sun x4500's, it is basically > a machine with 48 disks in it, no hardware RAID controller, so you have > to use software RAID, in our case mdadm because we're running RHEL 4.4. > > When we try to create the raid set (RAID6), we're getting an error: > "Invalid number of devices" (47 devices). We tried lowering the number, > and eventually it worked when we brought the number down to 27. But > looking at the source code, it looks like it supports up to 256 devices > for RAID6... ? Any insight would be much appreciated!! Use "--metadata=1" to mdadm. The 0.90 superblock has a limit of 27 devices. version 1 has no fixed limit, but the code might not support more than 384 very well. > > Thanks a million, That would be a megathank :-? NeilBrown