From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: Changing chunk size Date: Sun, 18 Feb 2007 15:17:57 -0500 Message-ID: <45D8B475.8070103@tmr.com> References: <45D4955C.60008@tmr.com> <17876.60347.983953.748979@notabene.brown> <45D5E05E.4000706@tmr.com> <45D7B12C.4010109@panix.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <45D7B12C.4010109@panix.com> Sender: linux-raid-owner@vger.kernel.org To: berk walker Cc: Neil Brown , Linux RAID List-Id: linux-raid.ids berk walker wrote: > > > Bill Davidsen wrote: >> Neil Brown wrote: >>> On Thursday February 15, davidsen@tmr.com wrote: >>> >>>> I have determined that a large array was created with an >>>> overly-large chunk size. Best way to resize? >>>> >>> >>> Dump and restore. >>> >>> in-place reshapes (such as raid5 + 1 disk => raid6 or >>> change-chunk-size) are on my list of 'that might be interesting to >>> implement', but there are plenty of more interesting things. And it >>> would be very slow. It would need to copy some number of stripes to a >>> backup somewhere, then copy them back in the new layout, so every >>> block in the array would be written twice. >> I'm sure "slow" is a relative term, compared to backing up TBs of >> data and trying to restore them. Not to mention the lack of >> inexpensive TB size backup media. That's totally unavailable at the >> moment, I'll live with what I have, thanks. > > >> If you were to be a gambler, Bill - Get 2 disks big enough to store >> your data, create a RAID5 mising one, and copy over the data. Re do >> the original array, and copy back. > Yeah, $0.02 doesn't buy much anymore. Besides, you'll be needing > bigger disks for the next machine you build,eh? Not unless the project leader say so. He can send me a note on a capital expenses approval form ;-) -- bill davidsen CTO TMR Associates, Inc Doing interesting things with small computers since 1979