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Re: [ccp4bb] raid array load question |
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CCP4bb navigationCCP4bb <-- 2008 <-- January 2008 <-- 15 January 2008Subject: Re: raid array load question From: Tim Gruene tg {- at -} SHELX {- dot -} UNI-AC {- dot -} GWDG {- dot -} DE Date: 2008-01-15 writes could then be tested by putting an ampersand ('&') at the end of the 'dd' command, couldn't they? And if you get tired of typing all the number, you could use the 'seq' command instead. Cheers, Tim > /bin/tcsh > set time > foreach file ( 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 ) > dd if=/dev/zero bs=2G count=1 of=/home/username/deleteme$file > end > > -James Holton > MAD Scientist > > > Harry M. Greenblatt wrote: >> BS"D >> >> To those hardware oriented: >> >> We have a compute cluster with 23 nodes (dual socket, dual core Intel >> servers). Users run simulation jobs on the nodes from the head node. At >> the end of each simulation, a result file is compressed to 2GB, and copied >> to the file server for the cluster (not the head node) via NFS. Each node >> is connected via a Gigabit line to a switch. The file server has a 4-link >> aggregated Ethernet trunk (4Gb/S) to the switch. The file server also has >> two sockets, with Dual Core Xeon 2.1GHz CPU's and 4 GB of memory, running >> RH4. There are two raid arrays (RAID 5), each consisting of 8x500GB SATA >> II WD server drives, with one file system on each. The raid cards are AMCC >> 3WARE 9550 and 9650SE (PCI-Express) with 256 MB of cache memory . >> When several (~10) jobs finish at once, and the nodes start copying the >> compressed file to the file server, the load on the file server gets very >> high (~10), and the users whose home directory are on the file server >> cannot work at their stations. Using nmon to locate the bottleneck, it >> appears that disk I/O is the problem. But the numbers being reported are a >> bit strange. It reports a throughput of only about 50MB/s, and claims the >> "disk" is 100% busy. These raid cards should give throughput in the >> several hundred MB/s range, especially the 9650 which is rated at 600MB/s >> RAID 6 write (and we have RAID 5). >> >> 1) Is there a more friendly system load monitoring tool we can use? >> >> 2) The users may be able to stagger the output schedule of their jobs, but >> based on the numbers, we get the feeling the RAID arrays are not performing >> as they should. Any suggestions? >> >> Thanks >> >> Harry >> >> >> ------------------------------------------------------------------------- >> >> Harry M. Greenblatt >> >> Staff Scientist >> >> Dept of Structural Biology harry.greenblatt@weizmann.ac.il >> >> >> Weizmann Institute of Science Phone: 972-8-934-3625 >> >> Rehovot, 76100 Facsimile: 972-8-934-4159 >> >> Israel >> >> > CCP4bb navigationCCP4bb <-- 2008 <-- January 2008 <-- 15 January 2008 |
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