How fast can I realistically expect an F740 to write out files doing a restore? I have an F740 that is currently doing nothing else, with a 10/100 Mbps Ethernet NIC connected to a Cisco 3548XL switch, and one shelf of 7x36GB drives. I'm dumping from a Sun E420R (4x450-MHz, 50GB Barracuda's on LSILogic Ultra2/LVD adapters) connected to the same switch via 1000base-SX. The command line used is:
ufsdump 0bf 128 - /dev/rdsk/c1t0d0s0 | rsh home-tape restore xbfD 128 - /vol/vol0/local
The F740 (home-tape) seems to be the bottleneck in this case:
# rsh home-tape sysstat 5 CPU NFS CIFS HTTP Net kB/s Disk kB/s Tape kB/s Cache in out read write read write age 100% 0 0 0 6316 104 29 6127 0 0 >60 99% 0 0 0 6396 106 28 6558 0 0 >60 100% 0 0 0 6356 105 24 7764 0 0 >60 100% 0 0 0 6316 104 40 7189 0 0 >60 93% 0 0 0 5983 99 28 6112 0 0 >60 100% 0 0 0 6395 106 28 6465 0 0 >60 99% 0 0 0 6272 104 51 8878 0 0 >60 100% 0 0 0 6506 107 36 6149 0 0 >60 [...]
An 8-hour restore window gives enough time to do about 150GB (which, coincidentally, is how much usable space is on 5x36GB data drives ;-)). Any performance tuning tips for doing a fast-as-possible disaster recovery restore like this? I'm going to try streaming data off tape next, instead of kludging it with a ufsdump, but it seems like the Netapp can't go any faster.
Is it possible to tell how much of the CPU is used up in rsh overhead, or TCP/IP overhead? Will I gain much if I used NDMP to stream the data to the filer? What about replacing the Fast Ethernet NIC with a Gigabit NIC that can offload packet checksumming from the main CPU? Anyone have numbers?