From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Nipper Subject: Re: Bad Hardware / Software Disk Detection for Production Systems Date: Fri, 2 Jun 2006 07:40:45 -0500 Message-ID: <20060602124045.GC16113@king.bitgnome.net> References: <8bdd70ae0606020521o177b840eya5580b511f3526a3@mail.gmail.com> Mime-Version: 1.0 Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com Content-Disposition: inline In-Reply-To: <8bdd70ae0606020521o177b840eya5580b511f3526a3@mail.gmail.com> List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Bill Rees Cc: reiserfs-list@namesys.com On 02 Jun 2006, Bill Rees wrote: > This is a general question but I thought I'd post it to the list to see if > anyone has any suggestions. You cannot expect any sort of data integrity if you are using JBOD mode on a RAID controller. The very nature of JBOD means that any time a single drive fails, you lose every partition across that entire JBOD volume. If your file systems are even coming back after such a catastrophe, you have been extremely fortunate to date. I still cannot imagine that you aren't losing data though since there is no mirroring going on whatsoever which means blocks are inherently being lost during such failures. If you are just looking for read performance, you should seriously consider at least a RAID 1 volume. If you can sacrifice some overall performance, you will get the best space optimization by going with a RAID 5. Anything more exotic than that, you should start at: --- http://en.wikipedia.org/wiki/Redundant_array_of_independent_disks and go with whichever level of RAID makes the most sense for your application. The bottom line is, you are going to lose data in a JBOD array (unless you also happen to be doing some sort of software RAID on top of that). There is really no gain through some sort of software trick to try to avoid the data loss. SMART enabled hard drives may occasionally warn you of an imminent failure, but then again, they may not. Drives will just occasionally fail entirely without any warning, hence the whole purpose of RAID levels above 0. -- Mark Nipper e-contacts: 832 Tanglewood Drive nipsy@bitgnome.net Bryan, Texas 77802-4013 http://nipsy.bitgnome.net/ (979)575-3193 AIM/Yahoo: texasnipsy ICQ: 66971617 -----BEGIN GEEK CODE BLOCK----- Version: 3.1 GG/IT d- s++:+ a- C++$ UBL++++$ P--->+++ L+++$ !E--- W++(--) N+ o K++ w(---) O++ M V(--) PS+++(+) PE(--) Y+ PGP t+ 5 X R tv b+++@ DI+(++) D+ G e h r++ y+(**) ------END GEEK CODE BLOCK------ ---begin random quote of the moment--- Anyone who is capable of getting themselves made President should on no account be allowed to do the job. -- Douglas Adams, _The Hitchhiker's Guide to the Galaxy_ ----end random quote of the moment----