On 6/30/2012 6:17 AM, Костырев Александр Алексеевич wrote: > So, you say that one should use this configuration in production with > hope that such failure would never happen?
No, I'm saying you are trolling. A concat of RAID1 pairs has reliability identical to RAID10. I don't see you ripping a mirror pair from a RAID10 array and saying RAID10 sucks. Your argument has several flaws. In a production environment, a dead drive will be replaced and rebuilt before the partner fails. In a production environment, the mirror pairs will be duplexed across two SAS/SATA controllers. Duplexing the mirrors makes a concat/RAID1, and a properly configured RAID10, inherently more reliable than RAID5 or RAID6, which simply can't be protected against controller failure. By stating the concat/RAID1 configuration is unreliable simply shows your ignorance of storage system design and operation. -- Stan > -----Original Message----- > From: dovecot-boun...@dovecot.org [mailto:dovecot-boun...@dovecot.org] On > Behalf Of Stan Hoeppner > Sent: Saturday, June 30, 2012 4:24 PM > To: dovecot@dovecot.org > Subject: Re: [Dovecot] RAID1+md concat+XFS as mailstorage > > On 6/28/2012 7:15 AM, Ed W wrote: >> On 28/06/2012 13:01, Костырев Александр Алексеевич wrote: > >>> somewhere in maillist I've seen RAID1+md concat+XFS being promoted as >>> mailstorage. >>> Does anybody in here actually use this setup? >>> >>> I've decided to give it a try, >>> but ended up with not being able to recover any data off survived >>> pairs from linear array when _the_first of raid1 pairs got down. > > The failure of the RAID1 pair was due to an intentional breakage test. > Your testing methodology was severely flawed. The result is the correct > expected behavior of your test methodology. Proper testing will yield a > different result. > > One should not be surprised that something breaks when he intentionally > attempts to break it. > >> This is the configuration endorsed by Stan Hoeppner. > > Yes. It works very well for metadata heavy workloads, i.e. maildir. >
