(sorry for disrupting the thread - copied this message from the archives) > I have set up a file server with LVM on top of RAID 5, and seem to be > having LVM related performance issue. Me too. > raid device: 118.2 MB/s > lvm device: 49.43 MB/s > file system: 40.83 MB/s Have you found an answer to that problem? I couldn't find anything helpful in the archives. Is this a general LVM on software RAID issue? I'm measuring a similar performance degradation on my system: plain Software RAID-5: # hdparm -t /dev/md3 /dev/md3: Timing buffered disk reads: 884 MB in 3.00 seconds = 294.49 MB/sec LVM2 logical volume: # hdparm -t /dev/data/temp /dev/data/temp: Timing buffered disk reads: 316 MB in 3.01 seconds = 105.15 MB/sec I tried changing the physical extent size, but this has almost no effect. Some short system information, I'll gladly provide more if needed: - kernel 2.6.17 - lvm2 LVM version: 2.02.06 (2006-05-12) Library version: 1.02.07 (2006-05-11) Driver version: 4.5.0 - 2x dual core xeon, 3 GHz - 6x WD360GD 36,7 GB SATA Disk - Software RAID-5 (chunk size: 256kB) --- Physical volume --- PV Name /dev/md3 VG Name data PV Size 167.45 GB / not usable 0 Allocatable yes PE Size (KByte) 4096 Total PE 42868 Free PE 4468 Allocated PE 38400 --- Volume group --- VG Name data System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 11 VG Access read/write VG Status resizable MAX LV 0 Cur LV 6 Open LV 0 Max PV 0 Cur PV 1 Act PV 1 VG Size 167.45 GB PE Size 4.00 MB Total PE 42868 Alloc PE / Size 38400 / 150.00 GB Free PE / Size 4468 / 17.45 GB --- Logical volume --- LV Name /dev/data/temp VG Name data LV Write Access read/write LV Status available # open 0 LV Size 10.00 GB Current LE 2560 Segments 1 Allocation inherit Read ahead sectors 0 Block device 253:5 Any hints are greatly appreciated. Thanks, Michael _______________________________________________ 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/
