On Fri, Jul 10, 2015 at 4:53 PM, Dax Kelson <dkelson@gurulabs.com> wrote: > My "root" LV is attached to a LVM Cache Pool that is about 900GB in size. > > The Origin/Slow LV can do about 560 MB/sec and the Fast/CacheLV can do > about double that speed. Here is the speed going directly against the Cache data LV and the OriginLV. [root@virthost03 tmp]# echo 1 > /proc/sys/vm/drop_caches [root@virthost03 tmp]# dd if=/dev/mapper/virthost03-CacheLV_cdata of=/dev/null count=1 skip=30 bs=1GB 1+0 records in 1+0 records out 1000000000 bytes (1.0 GB) copied, 1.08997 s, 917 MB/s [root@virthost03 tmp]# echo 1 > /proc/sys/vm/drop_caches [root@virthost03 tmp]# dd if=/dev/mapper/virthost03-root_corig of=/dev/null count=1 skip=30 bs=1GB 1+0 records in 1+0 records out 1000000000 bytes (1.0 GB) copied, 1.73674 s, 576 MB/s [root@virthost03 tmp]# Reading from the CacheLV is slower than even the OriginLV?!? [root@virthost03 tmp]# echo 1 > /proc/sys/vm/drop_caches [root@virthost03 tmp]# dd if=/dev/mapper/virthost03-root of=/dev/null count=1 skip=30 bs=1GB 1+0 records in 1+0 records out 1000000000 bytes (1.0 GB) copied, 6.77021 s, 148 MB/s _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
