On Fri, Jun 12, 2009 at 11:27 AM, Jean-Francois Malouin<[email protected]> wrote: > I can't get better than ~60MiBs to LTO4 tape when using amtapetype. > I tried 32k 1024k and 2048k, with and without hw compression enabled. > Any hints? I've added some info below. I can provide more upon request.
60 MiB/s is certainly capable of hitting a number of hardware bottlenecks - RAM, SCSI, PCI bus, even CPU when generating random data. You may want to try a simpler test with just 'dd' from e.g, /dev/zero and /dev/urandom. > Note that tapeinfo reports hw compression off but amtapetype says it > on. The changer web interface also tells me that the drive has > hardware compression off too. Puzzling. amtapetype detects compression by noting that it can fit more data on tape when using a fixed byte pattern than when writing pseudo-random data. Dustin -- Open Source Storage Engineer http://www.zmanda.com
