On Thu, May 13, 2010 at 9:09 AM, Roy Sigurd Karlsbakk <r...@karlsbakk.net>wrote:
> 1. even though they're 5900, not 7200, benchmarks I've seen show they are > quite good > They have a 64 MB cache onboard, which hides some of their slowness. But they are slow. > 3. what is TLER? > Time Limited Error Reporting, I think. It's a RAID feature where the drive will only try for X seconds to read a sector and then fail so that the RAID controller can take action. Non-RAID drives will tend to continue trying to read a sector for aeons before giving up leading to timeouts and whatnot further up the storage stack. For ZFS systems, this may not be too big of a deal. > 4. I thought most partitions were aligned at 4k these days? > > Nope. Most disk partitioning tools still use the old "start after 63 sectors for cylinder alignment", which creates a non-4 KB-aligned first partition, and thus non-aligned filesystems. This is why the WD Advanced Format drives come with a hardware jumper to shift numbering by 1 (partition is created at the 63rd logical sector, which is actually the 64th physical sector). However, Unix disk partitioning tools are getting better at this, and it seems that the new "standard" will be to create the first partition at the 1 MB mark. This is then aligned for everything up to 256 KB sectors or something like that. :) There's a list somewhere that shows the status of all the Linux partitioning tools. Not sure about Solaris. FreeBSD partitioning tools doesn't "do the right thing" yet, but allows you to manually specify the starting offset so you can manually align things. > We don't need too much speed on this system, we're still limited to 1Gbps > ethernet, and it's mostly archive data, no reads exceeding the ethernet > bandwidth > If you absolutely must use these drives, then download the wdidle3 utility, stick it on a DOS boot disk, attach the disk to a SATA port on the motherboard, boot to DOS, and disable the idle timeout. Do this for every disk, *before* you put it into the system where they'll be used. You'll save yourself a lot of headaches. :) And the drives will last longer than 3 months or so. (If they've removed the download for wdidle3, I have a copy here.) -- Freddie Cash fjwc...@gmail.com
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