What is a "Server Grade Hard Drive"?

I believe this has to do with the drive supporting the F_FULLFSYNC flush command (apparently not as common as would be ideal), which ensures that data sent to the drive for writing is actually written to disk before the disk claims it has been (normally, there's a cache that holds data before it actually gets to the disk, and a power failure at the wrong moment can result in lost data if the drive has claimed a successful write but not flushed the cache yet. There's some discussion here:

http://lists.apple.com/archives/darwin-dev/2005/Feb/msg00072.html

To people in the storage industry, server-grade may mean something different, as in a drive that has been certified for 24x7 operation with a very long mean time between failure.

cheers... -Adam

Here are a couple of links that address this issue:

<http://blogs.pcworld.com/staffblog/archives/006296.html>

<http://discussions.apple.com/thread.jspa?threadID=1343834&tstart=0>

<http://forums.macrumors.com/showthread.php?p=4851402>

Certainly in the old days, the store goes...the premium manufacturers (Apple, IBM, EMC, Sun etc) would go to Seagate, ask for 100 disk drives and take them back to their own factory. They'd traumatise them by running them hard in an environment and make it hotter and hotter until they start giving errors. They would generally follow a bell curve and the premium vendors would keep the 5 most resilient drives (or whatever percentage they chose) and send the rest back to Seagate who would sell them to people doing cheap volume disk drives in products or via retail.

Adam's description about supporting flushing is certainly a feature that would be desirable.

Certainly the assumption has to be that Apple hasn't gone out to the drive market and asked for the cheapest drives available regardless of any consequences that may come with that choice such as lower performance and higher failure rates.

On Feb 6, 2008 8:43 AM, craig963 <craigrichmond.echidna.id.au> wrote:

> Certainly the assumption has to be that Apple hasn't gone out to the drive
> market and asked for the cheapest drives available regardless of any
> consequences that may come with that choice such as lower performance
> and higher failure rates.

I guess that's my real question. All we can do is make assumptions of
what Apple means by "Server Grade Hard Drive". Apple doesn't mention
any specs on their webpage, and I haven't seen any sort of explanation
in press releases or advertisements.

I've been around long enough to know there can be quite a difference
in the way hard drives are built, and that includes the enclosure.
Like a lot of things, you pay more for something that's better built.
However, for now, it seems like "Server Grade Hard Drive" is just a
marketing slogan. After all, RAID 5 was designed to use cheap hard
drives. If one of the drives failed, you pull it out and pop in a
replacement without worrying about loss of data. With RAID 5, almost
any drive is "Server Grade".
--
David Weintraub
qazwartgmail.com