There is a slight performance related reason for exporting disk partitions individually, the performance boost is server-side as Paul says. The advantage is that the no_subtree_check can be used without any additional security risk.
It is probably the case that the /export/base/a is a partition, is exported with no_subtree_check, and therefore there is a small performance boost.
Preventing server side mount point traversal can also form part of a security mechanism if servers have different security options for different mount points, but in this case mounting server:/export/base wouldn't give you the same client view of the filesystem tree as mounting each individually if it worked at all.
Cheers, Sean
On 27 July 2016 at 23:21, Paul Heinlein heinlein@madboa.com wrote:
On Wed, 27 Jul 2016, Frank Thommen wrote:
Hello,
does it in any respect (throughput/performance, cpu load, I/O load, resilience, ...) matter, if one mounts subdirectories of an NFS (v3) export into separate directories or if one just mounts the parent directory?
I.e. like this:
server: /export/base/a -> /mnt/a server: /export/base/b -> /mnt/b server: /export/base/c -> /mnt/c server: /export/base/d -> /mnt/d server: /export/base/e -> /mnt/e
or simply like this:
server:/export/base -> /mnt
Performance wise, any bottleneck will almost certainly be tied to the disks on the back end, not the nfs process itself.
There are a couple good reasons for splitting up the mounts:
They can have different export restrictions (e.g., for different client hosts, ro vs. rw permissions, user squashing).
/base/[a-e] live on different RAID arrays and might benefit from different management cycles; that'd also be a case where multiple exports might be a good idea. That said, I've never managed an exported filesystem consisting of different arrays; we've always exported at the RAID level or below.
-- Paul Heinlein <> heinlein@madboa.com <> http://www.madboa.com/ _______________________________________________ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos