File Copy Painfully Slow

[Stringent]

I recently upgraded the hard drives in my home server. Its an Intel D945GCLF board, which is part of a Tranquil PC I bought ages ago. Its running Windows 2008 Server R2 as a DC. I have two hard drives mirrored using dynamic disks (yes not ideal, but considering what it does its fine).

Anyway, to copy my data across locally took AGES. I mean ages. On file copying it seems to slow right down to about 10MB/sec.

Once I got the mirror up and running, the resync runs fine at a reasonable speed. I do seem to remember a while back Agent stuck something up about file copying in Vista but I can't find it. Any one have any pointers?

If it were I/O errors with the hard drives I would expect the mirror resync to take over a day. But it didn't.

[smargh]

Are you copying from or to the disk which has the AD database? Running as a DC causes the write cache to be disabled.

I have no idea if this will be the cause of your problem, but it might be worth mentioning just in case.

[Agent]

Once I got the mirror up and running, the resync runs fine at a reasonable speed. I do seem to remember a while back Agent stuck something up about file copying in Vista but I can't find it. Any one have any pointers?

Most file speed copying issues in Vista were fixed with SP1 + latest drivers.
The bug only hit certain configs and wasn't across all Vista installs.

I'd be checking the usual suspects: Transfer protocol (although SATA largely makes this redundant), write caching, other files accessing the disk, lots of small files (bigger overhead), etc..

For any big transfers like this, and certainly for mirroring, I generally do them outside the OS (often through the recovery disk - it images disks much quicker IME)

[badass]

Are you copying from or to the disk which has the AD database? Running as a DC causes the write cache to be disabled.

This is a very important point. If the write cache on the HDD(s) is disabled, performance suffers really, really badly. Peak sustained write performance will drop to around 10% of a system with the write cache enabled.

[Stringent]

The 1TB disk is split into two partitions, the c: which has the OS and the AD database, and D which has all my stuff on it.

I stuck in the old dynamic disk and imported it and copied the data from that partition to the new partition. Then disconnected that, hooked up the drive to act as a mirror and then created the mirrors.

Installing stuff seems to be fine (like from D: to C as I keep a copy of programs on there). I doubt I am going to be doing any large transfers again for a while, but it would be good to know whats causing this!

MODs: Guessing this is a OS/Software issue, feel free to move if you like!