Re: How can I boost block I/O performance

[Avi Kivity]

Dave Pitts wrote:
> OK, I ran some tests, bypassing NFS, and got the following vmstat 
> display:
>
> procs -----------memory---------- ---swap-- -----io---- --system-- 
> ----cpu----
> r  b   swpd   free   buff  cache   si   so    bi    bo   in    cs us 
> sy id wa
> 4  1    696  80692    844 7225424    0    0    92 263924 14380  6176  
> 2 40 46 12
> 6  0    696 108668    784 7200936    0    0   456  6444 30515 20641  3 
> 57 36  3
> 5  1    696 100916    768 7211220    0    0   508 97276 31761 19916  3 
> 65 27  4
> 7  0    700  91188    764 7217340    0    0   428 121576 28704 21957  
> 3 69 24 3
> 3  3    700 103356    780 7204472    0    0   408 121748 29513 22603  
> 3 66 23 8
> 7  0    700  92836    780 7216168    0    0   360 43508 28784 21410  3 
> 54 33 11
> 7  0    700  88364    768 7224272    0    0   296 158236 26530 17570  
> 3 66 21 10
> 10  0    700  91068    776 7219096    0    0   444 141456 30306 16053  
> 3 74 16 7
> 5  2    700 102212    752 7206676    0    0   340 170076 29249 14872  
> 2 69 19 10
> 11  0    700  87884    768 7222096    0    0   392 143312 29743 19808  
> 1 65 23 11
> 8  0    700 104692    744 7204644    0    0   240 159624 25814 18747  
> 3 58 20 19
> 9  0    700 107196    736 7205196    0    0   344 148500 28191 18113  
> 3 70 21 6
> 16  1    700  99300    768 7211364    0   12   464 164348 25671 18326  
> 4 64 18 15
> 5  4    700 107412   1052 7204824    0    0   936 170904 28994 17062  
> 3 73 11 14
> 8  1    700  98892   1284 7217512    0    0   596 182708 31520 18424  
> 1 76 13 10
>
> This ia with 6 concurrent data streams. In addition to the 
> /proc/sys/vm/dirty* values I  also adjusted
> values in mm/page-writeback.c  eg. MAX_WRITEBACK_PAGES to 8192 . Our 
> goal is to blast out
> as much as possible per pdflush invocation.

These are healthier numbers. How many disks are on that machine? What 
raid level? Does it have battery backed up cache?

Anyway you need to check you network, since it looks like block 
throughput is not the issue.

--
error compiling committee.c: too many arguments to function

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