Grant Street wrote:
Just for completeness I am adding to this for future reference
This has stalled with redhat and I have had no correspondence on this
from the cachefs team.
Because of the architecture of isilon it defeats the cachefs caching
mechanism.
Grant
On 06/01/14 11:51, Grant Street wrote:
Hi
We are using EMC's Isilon storage as a NFS server consisting of over 50
storage and networking nodes. It presents itself as one hostname eg
isilon.sample.com and one very large directory tree, but dynamically
resolves to multiple IP addresses. These IP addresses have the advantage
of floating to different physical nodes in order to help balance the
networking load when thousands of clients are connecting.
The downside of this scheme is that currently cachefs would invalidate
the cache if the IP address (resolved from isilon.sample.com) changes on
reboot or automount expire and remount. This is because the cache key is
based on the IP address rather than the fqdn.
I have a case with redhat 00922150 and a bugzilla id 1018358. I was
wondering what your thoughts would be on changing the cache key to a
fqdn rather than an IP address?
Unfortunately with the size of the isilon cluster we would not be able
to do anything with traditional IP load balancers as the throughput and
number of clients is too high.
Looking at the code - it appears the 'key' for each NFS file system is
just a 'string of bytes' which include the IP address of the NFS server used
Assuming that the individual elements of the key are not used later,
then it should be simple to replace the IP address of the server with
the server's name in this key ?
I've just hacked the code to do just this by using clp->cl_hostname in
nfs_server_get_key() instead of the IP address
In simple tests, this appears to work fine when I mount/umount different
nodes of an Isilon server via its hostname - the cache is re-used
between these mounts - although the subsequent mounts of the same host
use a different IP address of the server
Is it correct to assume that the individual contents of 'key' are not
accessed once set? - i.e. it is just the whole key that is used?
If this does sound sensible, could an option (preferably a mount option)
be added to use the hostname of the server instead of the IP address?
Thanks
James Pearson
--
Linux-cachefs mailing list
Linux-cachefs@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/linux-cachefs
