Hello All-
I'm working on a Sun Ultra 80 M2 workstation. It has eight 750 GB SATA disks
installed. I've tried the following on both ON build 72, Solaris 10 update 4,
and Indiana with the same results.
If I create a ZFS filesystem using 1-7 hard drives (I've tried 1 and 7), and
then try to make an iSCSI target on that pool, when a client machine tries to
access the iSCSI volume, the memory usage on the Ultra 80 goes to the same size
as the ZFS filesystem. For example:
I'm creating a RaidZ ZFS pool:
zpool create -f telephone raidz c9d0 c10d0 c11d0 c12d0 c13d0 c14d0 c15d0
I then create a two terabyte filesystem on that zvol:
zfs create -V 2000g telephone/jelley
And make it into an iSCSI target:
iscsitadm create target -b /dev/zvol/dsk/telephone/jelley jelley
Now if I perform a 'iscsitadm list target', the iSCSI target appears like it
should:
Target: jelley
iSCSI Name:
iqn.1986-03.com.sun:02:fcaa1650-f202-4fef-b44b-b9452a237511.jelley
Connections: 0
Now when I try to connect to it with my Windows 2003 server running the MS
iSCSI initiator, I see the memory usage climb to the point that the totally
exhausts all available physical memory (prstat):
PID USERNAME SIZE RSS STATE PRI NICE TIME CPU PROCESS/NLWP
511 root 2000G 106M sleep 59 0 0:02:58 1.1% iscsitgtd/15
2139 root 8140K 4204K sleep 59 0 0:00:00 0.0% sshd/1
2164 root 3276K 2740K cpu1 49 0 0:00:00 0.0% prstat/1
2144 root 2672K 1752K sleep 49 0 0:00:00 0.0% bash/1
574 noaccess 173M 92M sleep 59 0 0:03:18 0.0% java/25
Do you see the iscsitgtd process trying to use 2000 gigabytes of RAM? I can
sit there and hold down spacebar while the Windows workstation is trying to
access it, and the memory usage climbs at an astronomical rate, until it
exhausts all the available memory on the box (several hundred megabytes per
minute). The total ram it tries to allocate depends totally on the size of the
iSCSI volume. If it's a 1000 megabyte volume, then it only allocates a gig...
if it's 600 gigs, it tries to allocate 600 gigs.
Now here is the real kicker. I took this down to as simple of a configuration
as possible--one single drive with a ZFS filesystem on it. The memory
utilization was the same. I then tried creating the iSCSI target on a UFS
filesystem. Everything work beautifully, and memory utilization was no longer
directly proportional to the size of the iSCSI volume.
If I create something small, like a 100 gig iSCSI target, the system does
eventually get around to finishing and releases the ram. When what's really
strange is when I try to access the iSCSI volume, the memory usage then climbs
megabyte per megabyte until it is exhausted, and then access to the iSCSI
volume is terribly slow.
I can copy a 300 meg file in just six seconds when the memory utilization on
the iscsitgtd process is low. But if I try a 2.5 gig file, once it get's about
1500 megs into it, performance drops about 99.9% and it's incredibly slow...
again, until it's done and the iscsitgtd releases the ram, then it's plenty
zippy for small IO operations.
Has anybody else been making iSCSI targets on ZFS pools?
I've had a case open with Sun since Oct 3, if any Sun folks want to look at the
details (case #65684887).
I'm getting very desperate to get this fixed, as this massive amount of storage
was the only reason I got this M80...
Any pointers would be greatly appreciated.
Thanks-
John Tracy
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