SQL db-file restoring to virtual disk is very slow!!!

[Igor_31]

We have ML370G3 Win2k Adv. server(SP4) & SQL2000(SP2).
This server is connected to MSA1000 by FCA2214. A logical drive where SQL db file is located is a virtual disk created by Virtual replicator (v.4.0).
A size of SQL mdf-file is 50 GB.
Recently we needed to restore the full database. We had a bak-file of the database created by SQL backup operation. This file we copied to this virtual disk.Then we tried to restore our database from this backup file.
A restore time was more 12 hours!
We were a very sad and embarrassed!
Recently we repeated this operation and took the same result!!
Advice us something how to decide thi problem/
Thank You.