Re: mdconfig device no faster then direct disk ...
On Mar 26, 2007, at 6:55 PM, Marc G. Fournier wrote: 45 processes: 1 running, 44 sleeping CPU states: 0.0% user, 0.0% nice, 0.4% system, 0.4% interrupt, 99.2% idle Mem: 35M Active, 285M Inact, 271M Wired, 44K Cache, 111M Buf, 402M Free Swap: 2007M Total, 2007M Free I just did: mdconfig -a -t malloc -s 200m -o reserve newfs /dev/md0 Now, my understanding, this builds a file system 'in core', vs on the disk ... with memory being faster then disk, I would have assumed that read/ write performance would have been better, but, using iozone, I'm not finding enough of a difference in performance to understand why I'd want to use a memory file system: In order to do useful disk benchmarks, you've got to perform I/O on large enough files that they don't fit into RAM. If you've got 400- odd MB completely unused according to top, you'd really like to use at least 1-2 GB worth of file data. Of course, trying to do I/O tests on a RAM disk means that you want the data to fit into RAM without swapping, which then means that trying to do identical testing between disk and RAMdisk doesn't really work too well. -- -Chuck ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
mdconfig device no faster then direct disk ...
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On a machine that is doing 0 swapping: last pid: 47437; load averages: 0.01, 0.01, 0.00 45 processes: 1 running, 44 sleeping CPU states: 0.0% user, 0.0% nice, 0.4% system, 0.4% interrupt, 99.2% idle Mem: 35M Active, 285M Inact, 271M Wired, 44K Cache, 111M Buf, 402M Free Swap: 2007M Total, 2007M Free I just did: mdconfig -a -t malloc -s 200m -o reserve newfs /dev/md0 Now, my understanding, this builds a file system 'in core', vs on the disk ... with memory being faster then disk, I would have assumed that read/write performance would have been better, but, using iozone, I'm not finding enough of a difference in performance to understand why I'd want to use a memory file system: aster# pwd /usr aster# iozone 180 | grep the file It then reads the file. It prints the bytes-per-second Reading the file...1.007812 seconds 54658803 bytes/second for writing the file 187280550 bytes/second for reading the file aster# pwd /usr aster# cd /mnt aster# df . Filesystem 1K-blocks Used Avail Capacity Mounted on /dev/md0 1981264 182272 0%/mnt aster# iozone 180 | grep the file It then reads the file. It prints the bytes-per-second Reading the file...0.984375 seconds 60701485 bytes/second for writing the file 191739611 bytes/second for reading the file Am I missing something here? Or is this expected? - Marc G. Fournier Hub.Org Networking Services (http://www.hub.org) Email . [EMAIL PROTECTED] MSN . [EMAIL PROTECTED] Yahoo . yscrappy Skype: hub.orgICQ . 7615664 -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.5 (FreeBSD) iD8DBQFGCHmb4QvfyHIvDvMRAugAAKDhsRHHeV/0LsQSGLNrLB6cDe2TDgCeMW3i PNL/GimacMHC5W6XWcyIOLo= =a4Tk -END PGP SIGNATURE- ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
