On 2014-09-08, Valeri Galtsev <galtsev at kicp.uchicago.edu> wrote: > > Then you too manage to stick with reliable drives! Performance... well, I > have array verify scheduled to start 23:00 on Saturday... also, on newer > controllers you can choose policy with highest priority for IO and lowest > for rebuild etc. I'm kind of sceptical about extra wear to mechanical > drives added by RAID check: my drives are always spinning full speed (no > spin down crap, thank you), and heads are not touching the platters... So, > I'm not certain there is extra wear. The only wear apart from bearings I > know about is when arm hits the stopper which only happens when you power > off the drive, which not the case here too. What do I miss? I learned the "reliable drive" lesson the hard way, when I accidentally ordered, and then unwisely decided to use, crappy drives. Fortunately no data was ever lost, but the drives made a lot of extra work for me. You may be 100% correct about wear. I have no actual evidence that extra verifies causes more wear than normal use. For my largest arrays, even if I started at 23:00 on Saturday, it would still be going through much of Sunday. Plus I have other disk operations that occur overnight. The performance loss isn't terrible during a verify, but I have noticed it enough that I prefer to avoid it happening so frequently. I've heard quite a few horror stories from people who never did a scrub of their arrays. But I haven't heard any from people who did scrubs less frequently than weekly. Has anyone? I'm genuinely curious; if there's a justification for weekly scrubs that's stronger than my fairly weak justifications for monthly, I'd switch back. --keith -- kkeller at wombat.san-francisco.ca.us