1. First of all, the Raid 1 has been connected with one (2xhdd) IDE M-S connector, after Raid 1 (2xhdd) connected on different ports IDE also increased performance but still was slow.
2. Then made these:
At the beginning export from NFS server was with these options:
/exported_dir 10.0.0.0/24(rw, no_root_squash, sync, no_wdelay)
After I changed the "sync" to "async" the write speed performance increase was quite large.
P.S: "no_wdelay" with "async" is neglected.
Try "man 5 exports" to see all available options for export
Note: on clients the /etc/fstab mount line is:
nisserv:/exported_dir /mount_path nfs defaults 0 0
The NFS server is on Piii 800MHz :D with 512MB Ram
Note: The man page says that async can be dangerous if the
NFS server daemon crashes as some data may not be committed to disk, but
this is always a risk (in my opinion anyways) since hard drives cache data
before it gets committed to disk anyways...
All the best, enjoy ;)