slice_async_rq. This limits the maximum number of asynchronous requests—usually write requests—that are submitted in one time slice. Default is 2. back_seek_max. Maximum distance (in Kbytes) for backward seeking. Default is 16384. back_seek_penalty. Used to compute the cost of backward seeking. Default is 2.
/sys/block/sda/queue/iosched/ slice_async_rq = cat /sys/block/sda/queue/iosched/ slice_async_rq /sys/block/sda/queue/iosched/slice_idle = cat /sys/block/sda/queue/iosched/slice_idle /sys/block/sda/queue/iosched/slice_sync = cat /sys/block/sda/queue/iosched/slice_sync, When changing this value, you can also consider tuning /sys/block/ /queue/iosched/ slice_a sync_rq (the default value is 2) which limits the maximum number of asynchronous requests—usually writing requests—that are submitted in one time slice. /sys/block/ /queue/iosched/low_latency, slice_async_rq – maximum asynchrounous requests (usually writes) to queue. If you increase quantum, you may also want to increase this. low_latency – try to keep latency low (at the cost of throughput). Defaults to 1? slice_idle – the time to wait after real work before starting on the idle queue. You can set this to 0 when you expect seeking to have minimal influence (e.g. on SSDs and many-disk SAN).
8/22/2011 · rm: cannot remove `nbd15/queue/iosched/ slice_async_rq ‘: Operation not permitted….. there are 25 lines like this …. When I do a vgsan I see this:Reading all physical volumes. This may take a.
Jika kita mengubah nilai ini, ada baiknya juga mentune /sys/block/ /queue/iosched/ slice_async_rq (nilai default adalah 2) yang akan membatasi jumlah maximum request asinkron – biasanya request untuk menulis – yang di lakukan dalam satu time slice. /sys/block/ /queue/iosched/low_latency, The async is mostly used by writes and since you’re willing to delay writing to disk, set both slice_async_rq and slice_async to very low numbers. However, setting slice_async_rq too low value may stall reads because writes cannot be delayed after reads any more.
cfqd-> cfq_ slice_async_rq = cfq_ slice_async_rq cfqd-> cfq_slice_idle = cfq_slice_idle cfqd-> cfq_slice_idle = blk_queue_nonrot (q) ? 0: cfq_slice_idle cfqd-> cfq_group_idle = cfq_group_idle cfqd-> cfq_latency = 1 cfqd-> hw_tag = – 1, 1/21/2018 · We’re working with a reasonably busy web server. We wanted to use rsync to do some data-moving which was clearly going to hammer the magnetic.
The conclusions are as follows when comparing file system throughput to block I/O throughput: * Same throughput for block sizes of 8 KB and above. * Better write throughput (+80%) and lower read throughput (-30%) for the 4 KB block size. * Lower throughput for small block sizes (512 bytes – 2 KB).
