on 3/26/2012 1:49 PM m.roth at 5-cent.us spake the following: > I believe I've posted before about one of the speed issues we were having, > of backups taking many, many hours that should *not* take that long. > > My manager and I finally nailed it down to the h/d itself. Identical > boxes, and he tried a backup of one system which took under two hours, > while the same regular one rand nearly six. > > I'd been googling on and off for weeks, and this morning, ran across > something: partition alignment. A thread where someone who'd done some > tests and found that was his problem. > > So, here's the answer: we have these Caviar Green 2tb drives (the thread I > found had either a 1tb, or 1.5tb), (and no, we are *NOT* going to buy > Caviar Green for servers ever again). The big thing is that they use 4k > sectors, *not* 512 bytes. Following directions, I pulled it into fdisk, > and then used a command I've not needed before: u. This changes units from > cylinders (the default) to sectors. Having done that, p shows that it > actually starts in sector 63. Again, following directions, I changed it to > start in sector 64. Finished the partition, wrote it, made the filesystem, > and tried it out. > > 177G transferred in 1h 47+m. > > So, anyone who's got new drives that use 4k sectors should probably follow > this. > > This also probably explains parted's completely aggravating complaint that > the partition's not aligned, but gives you no idea *why*, or how to align > it - I pulled the drive into parted, and told it to print, and it did > *not* complain the partition wasn't aligned. > > Next trick: hdparm. I want to disable, or at least shove way up, the > spindown timeout on these drives, which, depending on the thread you read, > is 6 or 8 seconds. hdparm should let me do that... but before I do, I'd > like to know what it's set at. Does anyone know how to find that out? And > no, the manpage is wrong, hdparm -B<no parm) /dev/sdx does *not* read it, > it just complains it's missing the parm. > > mark Isn't it sdparm for scsi and scsi emulations?