| 2011-11-01 16:49:07 |
Daniel Nichter |
description |
[In:<strong class="program">pt-diskstats</strong>]
/proc/diskstats displays sectors read and sectors written in columns #6 and #10. Sectors are typically 512b units, however pt-diskstats assumes one sector = 1kb. Therefore, it would be best either to rename them to "rd_avsct" and "wr_avsct", or divide the number by 2 to display kilobytes.
Here's a sample that clearly shows that numbers do not add up. I've written 1MB with dd using oflag=direct bs=131072 count=8:
#ts device rd_s rd_avkb rd_mb_s rd_mrg rd_cnc rd_rt wr_s wr_avkb wr_mb_s wr_mrg wr_cnc wr_rt busy in_prg
{1} sdb 0.0 0.0 0.0 0% 0.0 0.0 7.9 256.0 1.0 0% 0.0 0.0 0% 0
Thank you,
Aurimas |
/proc/diskstats displays sectors read and sectors written in columns #6 and #10. Sectors are typically 512b units, however pt-diskstats assumes one sector = 1kb. Therefore, it would be best either to rename them to "rd_avsct" and "wr_avsct", or divide the number by 2 to display kilobytes.
Here's a sample that clearly shows that numbers do not add up. I've written 1MB with dd using oflag=direct bs=131072 count=8:
#ts device rd_s rd_avkb rd_mb_s rd_mrg rd_cnc rd_rt wr_s wr_avkb wr_mb_s wr_mrg wr_cnc wr_rt busy in_prg
{1} sdb 0.0 0.0 0.0 0% 0.0 0.0 7.9 256.0 1.0 0% 0.0 0.0 0% 0
Thank you,
Aurimas |
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