From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: Changing chunk size Date: Fri, 16 Feb 2007 11:48:30 -0500 Message-ID: <45D5E05E.4000706@tmr.com> References: <45D4955C.60008@tmr.com> <17876.60347.983953.748979@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <17876.60347.983953.748979@notabene.brown> Sender: linux-raid-owner@vger.kernel.org To: Neil Brown Cc: Linux RAID List-Id: linux-raid.ids 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. -- bill davidsen CTO TMR Associates, Inc Doing interesting things with small computers since 1979