I'm in the middle of building up a new home server - looking at RAID-5 or 6 and 2.6.x, so maybe it's time to look at all this again, but it sounds like the auto superblock update might thwart it all now...
Nah... As far as I can tell, 20ms after the last write, the auto superblock update will write the array as clean. You can then spin the disks down as you normally would after a delay. It's just like a normal write. There is an overhead I guess, where prior to the next write it's going to mark the superblocks as dirty. I wonder in your case if this would spin up *all* the disks at once, or do a staged spin up, given it's going to touch all the disks "at the same time"?
I have my Raid-6 with ext3 and a commit time of 30s. With a idle system, it really stays idle. Nothing touches the disks. If I wanted to spin them down I could do that.
The thing I *love* about this feature, is when I do something totally stupid and panic the box, 90% of the time I don't need a resync as the array was marked clean after the last write. Thanks Neil!
Just for yuk's, here are a couple of photos of my latest Frankenstein. 3TB of Raid-6 in a Midi-Tower case. Had to re-wire the PSU internally to export an extra 12v rail to an appropriate place however.
I have been beating Raid-6 senseless for the last week now and doing horrid things to the hardware. I'm now completely confident in its stability and ready to use it for production. Thanks HPA!
http://www.wasp.net.au/~brad/nas/nas-front.jpg http://www.wasp.net.au/~brad/nas/nas-psu.jpg http://www.wasp.net.au/~brad/nas/nas-rear.jpg http://www.wasp.net.au/~brad/nas/nas-side.jpg
Regards, Brad -- "Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so." -- Douglas Adams - 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
