> dd_rescue /dev/vg_main/storagelv /dev/null > > dd_rescue: (info): ipos: 138384.0k, opos: 138384.0k, xferd: 138384.0k > errs: 0, errxfer: 0.0k, succxfer: 138384.0k > +curr.rate: 27966kB/s, avg.rate: 27553kB/s, avg.load: 20.9% This proves nothing I'm afraid. I've done similar tests myself and even gotten bonnie to produce results that "look good", but these are all synthetic benchmarks. What counts is realworld performance. I tested bonnie (locally on lvm and regular partitions) and regular filecopy with time (using a 512MB file) between LVM to the system drive. Also tried NFS compared to Samba and it made no difference. FTP proved the same. At the beginning of all the test where I could see the actual speed, it would be right on spot (ie, maxing out my 100mbit switched network) but after 10 seconds or so, the speed would drop dramatically to 2-4mb/s (from ~9mb/s) and then even halt completely for a short while and then resuming at 2-4mb/s (and this with no other network/disk access on the server). Oh, and to eliminate the destination drive completely during tests, I also tried "time cat big512mbfile > /dev/null", which, ofcourse, resulted in the same speed as every other test I did. This is starting to become a pain. For example, I'm unable to burn my backup tarfiles to DVD over the network without empting the buffer (thank good for powerburn) which is ridiculous since all it requires is a consistant 4mb/s or so. I'm going to try the devicemapper in 2.6 (LVM2), but I haven't had the time to do it yet (have to create a similar setup since I dont want to risk the data for a little test). Oh, and before you ask, the server is a Celeron@2Ghz, with 512MB memory, all filesystems are ext3, all drives are master and use the correct ATA/133 cable. All drives use dma and 32bit with sync transfers. The server's sole purpose in life is to provide storage for my network. It uses an nice Intel Pro/100 card to ensure stability and performance. The network is 100mbit full duplex switched to allow max speed. When transfering files from a normal partition (ie, /dev/hdax) I get about 9-9.5mb/s with samba and Win2kPro (measured with the Kerio Firewall on the Win2k and IpTraf locally on the fileserver). (The serverhardware was purchased since I figured that my previous 120Mhz Pentium Classic was the bottleneck :-/ ) /Henric _______________________________________________ linux-lvm mailing list linux-lvm@sistina.com http://lists.sistina.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
