On Wed, Mar 24, 2010 at 7:49 AM, Eric Shubert <ejs@xxxxxxxxxx> wrote: > Mark Knecht wrote: >> >> Hi, >> Just triple checking what I think I've learned here before I start >> loading Gentoo. Parts are arriving and I'm staring to put them >> together to build a combo low-use server (backups and MythTV) as well >> as desktop for my wife. I can do anything up to 6 drives but want the >> RAID to survive in the face of possibly two drive failure. This is all >> low bandwidth stuff. >> >> I'm fairly focused at this point on doing RAID1 using 3 drives. >> Unless I hear differently I believe a 3-drive RAID1 could survive 2 >> drive failures, and as well any single drive could be taken to another >> machine or even placed in an external USB/eSATA drive container in the >> event of some major motherboard failure. Is any of that incorrect? > > All sounds right to me. Just be sure that the array is defined with 3 drives > and no spares. > >> Also, along the way folks have mentioned hot spares but I'm not >> seeing that a hot spare does much for RAID1. Am I incorrect about >> that? > > Right. The only thing it would buy you is a little write performance, but > you'd lose a little read performance, and take a performance hit if/when one > drive goes off. > >> Granted, I guess the rebuild starts automatically and maybe >> that's worth it, but I'm thinking that mdadm can probably let me know >> fairly quickly that I need to do some work. I've purchased 6 drives so >> I'll have 2 or 3 spares around and I can do a hot spare but I don't >> see the value in spinning the drive for a year burning power and >> wearing the drive out vs. just putting it on the shelf and keeping it >> in reserve for a rainy day. > > Just one thought here. There is a certain "infant mortality syndrome" that > drives experience (according to google study). I would rotate drives from > the shelf into service after a year or so, while they're still under > warranty (assuming 3yr warranty). If the warranty period is less than 2yr, > rotate them sooner. > > NJoy! > > -- > -Eric 'shubes' Thanks Eric. I'll keep this in mind. Other than the work involved in fixing things this is a home setup so if it was down for a day or two it's not like a mission critical or anything. Also, the really critical coming from another machine that has two RAID's in it: 1) Main RAID is RAID0 using RAID class drives. (Lower reliability but speed where I need it.) 2) Backup RAID in first machine is a 3 drive RAID 1. 3) This 2nd machine which also has RAID1 as we've been speaking aobut. So, machine 1 runs RAID0 for work and then automatically backs up data every few hours to a RAID1 internal to the same box. Once a day I will then back up the machine 1 RAID1 to machine 2's RAID1 so I'm covered twice. If one RAID1 does down then I can basically just fix it will the other RAID1 keeps me safe. Certainly, every so often I go offsite for even more protection. Cheers, Mark Cheers, Mark -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
