I would look at what size IOs you are doing in each case. I have been playing with a T5240 and got 400Mb/s read and 200Mb/s write speeds with iozone throughput tests on a 6 disk mirror pool, so the box and ZFS can certainly push data around - but that was using 128k blocks.
You mention the disks are doing bursts of 50-60M which suggests they have more bandwidth and are not flat out trying to prefetch data. I suspect you might be IOPS bound - if you are doing a serial read then write workload and only doing small blocks to the tape it might lead to higher service times on the tape device hence slowing down your overall read speed. It its LTO-4 try and up your block size as big as you can go - 256k, 512k or higher and maybe use truss on the process to see what read/write sizes its doing. I also found the iosnoop dtrace tool from Brendan Greg's dtrace toolkit to be very helpful in tracking down these sorts of issues. HTH. Cheers, Adrian -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
