Hi! I have set up an LVM VolumeGroup with 22 model 3390-3, shown below. I have my Linux communication set up with IUCV in VM:s TCP/IP. And I use a 2216 with 100Mb speed. I then mounted an NT-server to copy the entire server to my new LVM VG001 mounted as /images. The storage size for my Linux-machine was 64Mb.
" # mount -t smbfs -o username=maer10,workgroup=CDSHBNT //sths0038/images /slask" "mount /dev/vg001/images /images" I copied from /slask to /images with "cpio -pmud /images" The speed of the cpio copy was really slow! The copy rate was approx. 0,3Mb/sec or 1,381714Mb/hour. It took 30 hours to copy 42Gb! It was'nt much CPU-consuming. In theory the 2216 100Mbit-line should transfer 12,5Mb/sec, but in practise I beleive it should transfer data at a speed of 4 - 5Mb/sec. To compare the speed, I started an TSM Selective Backup of the LVM dasd /images. The speed was faster than the cpio (maybe the "smbfs" was a slow companion). TSM transfered the data 1.02Mb/sec. A second run with TSM and with compression off, gave a transfer of 2,8Mb/sec at the very best. A third run with TSM and with the TXNBYTELIMIT set to 25600, gave a transfer of 2,152Mb/sec. An FTP-transfer of a 8.8Mb file on the LVM /images to another Linux-machine on the same hardware took 283,93Kb/sec. I also did a compare with writing directly to the LVM /images with the following command: time dd if=/dev/zero of=/images/100MB2bv bs=1024k count=100 This write to disk took at the very best 35 seconds to write 100Mb. We run a script that did simultanously 10 different writes to the same LVM /images. It took between 0.37 minutes up to 2minutes to complete the different writes. Now we restarted the Linux-machine with a storagesize of 128Mb and run the script with the 10 different writes one more time. Now the writes took beteween 1 minute up to 3 minutes to complete! ---------------------------------- I run a test on a different VM-machine to a single full-dasdvolume 3390-3 without LVM. As you see it took 22.8 sec to write 100Mb to dasd. The second run took 7.0 sec. x2vm:~ # time dd if=/dev/zero of=/shb/cdcis/100MB bs=1024k count=100 100+0 records in 100+0 records out real 0m22.881s user 0m0.010s sys 0m21.460s x2vm:~ # time dd if=/dev/zero of=/shb/cdcis/100MB bs=1024k count=100 100+0 records in 100+0 records out real 0m7.073s user 0m0.000s sys 0m4.700s Now to my question, is there anyone who have experience of the LVM to get a better performance? Should there be another stripesize or a different number of stripes? Should the cpio-copy via smbfs work so slow (0,3Mb/sec)? Here follows the Volume Group Display: mammut:/usr/src # vgdisplay -v --- Volume group --- VG Name vg001 VG Access read/write VG Status available/resizable VG # 0 MAX LV 256 Cur LV 1 Open LV 1 MAX LV Size 255.99 GB Max PV 256 Cur PV 22 Act PV 22 VG Size 50.36 GB PE Size 4 MB Total PE 12892 Alloc PE / Size 12892 / 50.36 GB Free PE / Size 0 / 0 VG UUID olSnNp-jhom-fds7-kfg5-Y5Dp-1X4L-ZYYyGr --- Logical volume --- LV Name /dev/vg001/images VG Name vg001 LV Write Access read/write LV Status available LV # 1 # open 1 LV Size 50.36 GB Current LE 12892 Allocated LE 12892 Stripes 22 Stripe size (KByte) 16 Allocation next free Read ahead sectors 120 Block device 58:0 --- Physical volumes --- PV Name (#) /dev/dasdd1 (1) PV Status available / allocatable Total PE / Free PE 586 / 0 .............etc....to dasdy1 PV Name (#) /dev/dasdy1 (22) PV Status available / allocatable Total PE / Free PE 586 / 0 Regards Bertil Starck
