Messages in this thread | | | Date | Fri, 16 Oct 2009 17:46:18 -0400 (EDT) | From | Justin Piszcz <> | Subject | 3ware 9650SE-4PML RAID-1 Question: One reader process starves I/O to the rest of the system? |
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Hello,
I tried CFQ/deadline schedulers, when I run the following:
# /usr/bin/time dd if=/dev/sdb2 of=/raid6/sdb2.img
Behind which are 2 x Raptor 150GB disks, the system is pretty much unusable when I control-c the dd, it comes back to life.
The RAID-6 is a 15-disk RAID-6 which does 600-700MB/s writes.
All cards are on PCI-e and have adequate bandwidth on a P55 board (DP55KG).
Are there any recommended tuning options for a RAID-1 configuration, such that a heavy I/O read or write operation does not pause the system?
During the dd..
Drive Performance Monitor Configuration for /c1 ... Performance Monitor: ON Version: 1 Max commands for averaging: 100 Max latency commands to save: 10 Requested data: Instantaneous Drive Statistics
Queue Xfer Resp Port Status Unit Depth IOPs Rate(MB/s) Time(ms) ------------------------------------------------------------------------ p0 OK u0 25 762 26.219 19 p1 OK u0 23 780 25.953 24 p2 OK u1 1 0 0.000 98 p3 NOT-PRESENT - - - - -
Justin.
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