-----Original Message----- >From: Ted Mittelstaedt <t...@mittelstaedt.us> > >On 4/30/2011 7:28 PM, typo W wrote: >> Hi, I'm brand new to virtualbox, so pardon me in case I made stupid >> mistakes. I created a FreeBSD guest out of the regular virtualbox >> port (3.2.12) on FreeBSD 8.2, then timed the copying of a 320MB >> binary file to another file, which took 4 seconds, ie, 80MB/s. On an >> identical hardware I created a CentOS guest out of KVM running on >> CentOS, and the same operation only takes 1 second. On both hosts, >> the copy takes 1 second. That is, virtualbox slowed the copying to >> 1/4 speed on my guest FreeBSD. >> >> Both hosts are Dell R710, with 6 x 600GB 15K SAS drives forming a >> RAID6 with R700 controller with 512MB cache. >> > >Try some file copies at the base OS and let us know the results. > >I would guess that the FreeBSD hardware RAID device driver for >the R700 controller isn't using the hardware write caching of >the controller. When the FreeBSD host OS got the file write >call from the virtual box it should have issued the write to the >disk controller and then returned immediately since the write should >have gone into the hardware cache of the controller. > >you can also try playing with the sync/async options in the host OS. >See the mount command for details. it is kind of pointless to do >sync writes on a caching hardware controller because the entire >point of sync writes is to keep the data from being scrambled >in a crash or if there is sudden power loss - but the cache in the >hardware array card is more than capable of screwing the filesystem >if that happens. > >Ted > >
On both the FreeBSD host and the CentOS host, the copying only takes 1 second, as tested before. Actually, the classic "dd" test is slightly faster on the FreeBSD host than on the CentOS host. The storage I chose for the virtualbox guest is a SAS controller. I found by default it did not enable "Use Host I/O Cache". I just enabled that and rebooted the guest. Now the copying on the guest takes 3 seconds. Still, that's clearly slower than 1 second. Any other things I can try? I love FreeBSD and hope we can sort this out. Thanks, John _______________________________________________ freebsd-emulation@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-emulation To unsubscribe, send any mail to "freebsd-emulation-unsubscr...@freebsd.org"
