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' -- 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
