NFS FAQ review
Subsystems (2)
Anyone know why Chuck is getting unsubscribed from this list?
Anyway, see below for revised FAQ information.--b.
----- Forwarded message from "Lever, Charles" <[email protected]> -----
From: "Lever, Charles" <[email protected]>
To: "J. Bruce Fields" <[email protected]>
can you post this to the list?
apparently i've been booted off again...
Quoted 19 lines
-----Original Message-----
From: Lever, Charles
Sent: Monday, October 18, 2004 4:50 PM
To: [email protected]
Subject: NFS FAQ reviewplease see:
http://nfs.sourceforge.net/new.php
changes include:
o removal of most references to 2.2 and 2.5 o new introduction o cleanup of "quick" sections o update of NFSv4-related items o various minor fixes
Quoted 8 lines
comments, please. i'd like to roll this in to index.php sometime this week.
- Chuck Lever
--corporate: <cel at netapp dot com> personal: <chucklever at bigfoot dot com>
----- End forwarded message -----
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G'day,
Quoted 19 lines · J. Bruce Fields
Quoted 19 lines
-----Original Message-----
From: Lever, Charles
Sent: Monday, October 18, 2004 4:50 PM
To: [email protected]
Subject: NFS FAQ reviewplease see:
http://nfs.sourceforge.net/new.php
changes include:
o removal of most references to 2.2 and 2.5 o new introduction o cleanup of "quick" sections o update of NFSv4-related items o various minor fixes
Quoted 3 lines
Quoted 3 lines
comments, please. i'd like to roll this in to index.php sometime this week.
Nice job. I took the opportunity to go through the whole doc and offer some comments.
Quoted 3 lines
Quick Server Setup Guide:
3. Use
/etc/init.d/nfsstart to start the NFS server.
On some distros, you want /etc/init.d/nfsserver and .../nfs is used on the client side.
Quoted 2 lines
Quick Client Setup Guide
5. Start the NFS locking service with/etc/init.d/nfslockstart.
This isn't necessary with modern kernels, which start the lockd kernel thread automatically on the first NFS mount.
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A1
NFS Version 2 requires that a server must save all the data in a write operation to disk before it replies to a client [...]
Another reason this is slow on some machines is that the page size is larger than 8K so the server has to wait to read in data from the file to fill the remainder of the page before it can overwrite other data.
Quoted 5 lines
B1
Are you using enough NFS daemons for your UDP mounts? Look at the network traffic with netstat -s -t; if the number of packet receive errors increases during heavy NFS usage, increase the total number of nfsd's.
?!?? Why would you look at TCP stats to diagnose UDP performance problems? Why would packet receive errors be indicative of not enough nfsds? Perhaps you could just copy in some of Neil's explanation of the "th" line in /proc/net/rpc/nfsd
http://marc.theaimsgroup.com/?l=linux-nfs&m=102824853219024&w=2
Quoted 6 lines
B2
Finally, note that the maximum transfer size permitted by the Linux server (NFSSVC_MAXBLKSIZE) is set to 32 KB when applying all patches involved with the implementation of NFS over TCP in the 2.4 kernels. Later 2.4 kernels have TCP server support already integrated, but keep the transfer size support limited to 8KB.
Even later 2.4 kernels have a transfer size which is twice the server's page size, up to a maximum of 32KB.
Quoted 2 lines
B5. Why does default NFS Version 2 performance seem equivalent to NFS Version 3 performance in 2.4 kernels?
The other reason (when the server is a 4K page machine like an i386) is the transfer size is limited to 8KB. With a 2.6 kernel, transfer sizes up to 32KB allow Version 3 to make more efficient use of the network.
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B9. I use the "sync" or "noac" mount options. I've increased my wsize, but write throughput is lower than I expect. Why is this?
Another possible factor arises when the server's page size is larger than the client's. The Linux client aligns reads and writes to it's own page size, which may be unaligned on the server. Depending on the server OS and filesystem, this could result in a number of performance limiting problems.
Quoted 4 lines
D2
These files are the result of a 'sillydelete' operation. One process on the client is trying to delete the file while another has it open.
Or the same process.
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D3.
It refers to a mount request by a Solaris system that is trying to get ACL information - which linux obviously does not have.
There are patches to do that and some distros ship with them, SUSE in particular.
Quoted 4 lines
E1
However, older SunOS and Tru64 clients take advantage of the NFS specification by making all NFS file lock requests with the credentials of the daemon
We've seen this with HP-UX clients too.
Greg.
Signature · 14 lines
Greg Banks, R&D Software Engineer, SGI Australian Software Group. I don't speak for SGI. ------------------------------------------------------- This SF.net email is sponsored by: IT Product Guide on ITManagersJournal Use IT products in your business? Tell us what you think of them. Give us Your Opinions, Get Free ThinkGeek Gift Certificates! Click to find out more http://productguide.itmanagersjournal.com/guidepromo.tmpl _______________________________________________ NFS maillist - [email protected] https://lists.sourceforge.net/lists/listinfo/nfs