Services for NFS
NFS performance will increase when changing from the default
of synchronous writes to asynchronous writes.
To change from synchronous to asynchronous writes (and vise
versa), open the Web UI and click Shares, Sharing Protocols.
Choose the NFS Protocol, and click Properties. Click the NFS
Async/Sync Setting button to toggle between asynchronous and
synchronous writes.
NOTE: After toggling between synchronous and asynchronous writes (and
vise versa), the NFS server service must be restarted. Inform all users before
restarting the service.
Keep the following in mind when toggling between synchronous
and asynchronous writes.
1.
When the caching setting for Services for NFS is set to
asynchronous writes (caching on), NFS clients may
incorrectly assume that all the writes were safely committed
to stable storage; the writes are only in the Services for NFS
cache.
2.
For asynchronous writes: Although Server for NFS informs
the NFS client that the data has been safely written to disk,
the data is still stored in cache, and is waiting to be written to
disk. This might cause file corruption issues if, for example,
you lose your power supply to the Server for NFS server
while data is still in the cache. At this point, the NFS client
assumes that data that was lost was actually safely written to
disk.
3.
With synchronous writes on (caching off), all write requests
are immediately committed to disk before a response is sent.
Although synchronous writes “on” does frequently slow
NFS file writes, it does improve the stability and data
integrity.
6
HP StorageWorks NAS 1200s Release Notes
HP CONFIDENTIAL
Writer: Ron Reisdorf File Name: 352556-001
Codename: Rambler Part Number: 352556-001 Last Saved On: 11/7/03 12:17 PM
