On Sun, Apr 12, 2009 at 12:23:03PM -0700, Richard Elling wrote:
> These disks are pretty slow. JBOD? They are not 100% busy, which
> means that either the cached data is providing enough response to the
> apps, or the apps are not capable of producing enough load -- which
> means the bottleneck may be elsewhere.
They are four 500-gig Iscsi LUNs exported from a Netapp filer, with
Solaris multipathing. Yes, the I/O is normally mostly writes, with
reads being satisfied from various caches.
> You can use fsstat to get a better idea of what sort of I/O the applications
> are seeing from the file system. That might be revealing.
Thanks for the suggestion. There are so many `*stat' commands that I
forget about some of them. I've run a baseline with `fsstat', but the
server is mostly idle now. I'll have to wait for another incident!
What option to `fsstat' do you recommend? Here's a sample of the
default output:
$ fsstat zfs 5 5
new name name attr attr lookup rddir read read write write
file remov chng get set ops ops ops bytes ops bytes
3.56M 1.53M 3.83M 1.07G 1.53M 2.47G 4.09M 56.4M 1.83T 61.1M 306G zfs
13 1 16 1.40K 5 11.6K 0 5 38.5K 125 127K zfs
18 0 18 3.61K 6 21.1K 0 6 16.7K 97 244K zfs
26 4 25 1.73K 10 6.76K 0 18 178K 142 817K zfs
12 3 13 3.90K 5 9.00K 0 5 32.8K 108 287K zfs
7 2 7 1.98K 3 5.87K 0 7 67.5K 108 2.34M zfs
--
-Gary Mills- -Unix Support- -U of M Academic Computing and Networking-
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