I tried as you suggested, but I notice that output from iostat while doing dd if=/dev/dsk/... still shows that reading is done in 56k chunks. I haven't see any change in performance. Perhaps iostat doesn't say what I think it does. Using dd if=/dev/rdsk/.. gives 256k, and dd if=zfsfile gives 128k read sizes.
On 5/15/07, Jonathan Edwards <[EMAIL PROTECTED]> wrote:
On May 15, 2007, at 13:13, Jürgen Keil wrote: >> Would you mind also doing: >> >> ptime dd if=/dev/dsk/c2t1d0 of=/dev/null bs=128k count=10000 >> >> to see the raw performance of underlying hardware. > > This dd command is reading from the block device, > which might cache dataand probably splits requests > into "maxphys" pieces (which happens to be 56K on an > x86 box). to increase this to say 8MB, add the following to /etc/system: set maxphys=0x800000 and you'll probably want to increase sd_max_xfer_size as well (should be 256K on x86/x64) .. add the following to /kernel/drv/sd.conf: sd_max_xfer_size=0x800000; then reboot to get the kernel and sd tunings to take. --- .je btw - the defaults on sparc: maxphys = 128K ssd_max_xfer_size = maxphys sd_max_xfer_size = maxphys _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
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