<!-- keep this as a security measure: * Set ALLOWTOPICCHANGE = Main.TWikiAdminGroup,Main.LCGAdminGroup * Set ALLOWTOPICRENAME = Main.TWikiAdminGroup,Main.LCGAdminGroup #uncomment this if you want the page only be viewable by the internal people #* Set ALLOWTOPICVIEW = Main.TWikiAdminGroup,Main.LCGAdminGroup --> KeyWords: _(see the KeyWords page for guidelines on what to put here.)_ ---+ Performance measurements from a single Thor To be able to make long-term calculations about bandwidth requirements in the Phoenix Cluster we need an accurate and round number to work with, when talking about how much data bandwidth can a Thor give. ---++ Disk layout * There are 5 Raid6 arrays made of 7+2 disks, and three spare disks * Those five arrays are joined together in a volume group, then a logical volume, and then a xfs filesystem * All with default values. ---+++ Performance The disk performance to be around 700 MB/s using Bonnie++ Then, we tried to measure how much the clients can get out of it. We use dccp transfers to /dev/null * With 2 wn, 15 or 20 transfers per WN, we get 450 MB/s * Above that, even with 90 transfers per WN, we get 500 MB/s. * One single WN with 45 transfers gets only 310 MB/s * Putting three WNs doesn't increase the 500 MB/s boundary * The write speed for one WN and 45 transfers at the same time is 70 MB/s All in all, we can determine that each Thor can serve up to *500 MB/s read speed* to the clients. ---++ Another disk layout - with raid0 We realised that, from a single transfer, you only access one of the five raid6s. That's because creating a volume group is not the same as creating a stripped raid0 (looks like it creates a jbod). So, we tried making a raid0 on top of all raid6s. The rest is the same as before ---+++ Performance * Write speed, from 2 WNs and 23 transfers each, we get *270 MB/s write speed* peaks. ---++ Readers' comments %COMMENT{type="below"}%
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Topic revision: r1 - 2010-08-31 - PabloFernandez
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