[gpfsug-discuss] LROC nvme small IO size 4 k

[Matt Weil]

I still see small 4k IO's going to the nvme device after changing the
max_sectors_kb.  Writes did increase from 64 to 512.  Is that a nvme
limitation.
> [root at ces1 system]# cat /sys/block/nvme0n1/queue/read_ahead_kb
> 8192
> [root at ces1 system]# cat /sys/block/nvme0n1/queue/nr_requests
> 512

> [root at ces1 system]# cat /sys/block/nvme0n1/queue/max_sectors_kb
> 8192
> [root at ces1 system]# collectl -sD --dskfilt=nvme0n1
> waiting for 1 second sample...
>
> # DISK STATISTICS (/sec)
> #
> <---------reads---------><---------writes---------><--------averages-------->
> Pct
> #Name       KBytes Merged  IOs Size  KBytes Merged  IOs Size  RWSize
> QLen  Wait SvcTim Util
> nvme0n1      47187      0  11K    4   30238      0   59  512
> 6     8     0      0   34
> nvme0n1      61730      0  15K    4   14321      0   28  512
> 4     9     0      0   45


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