Flashcache¶

До fashcache

monkey ~ # fio -readonly -name iops -rw=randread -bs=4096 -runtime=20 -iodepth 1 -filename /dev/vda -ioengine libaio -direct=1
iops: (g=0): rw=randread, bs=4K-4K/4K-4K, ioengine=libaio, iodepth=1
fio 2.0.7
Starting 1 process
Jobs: 1 (f=1): [r] [100.0% done] [482K/0K /s] [117 /0  iops] [eta 00m:00s]
iops: (groupid=0, jobs=1): err= 0: pid=2941
  read : io=8892.0KB, bw=455156 B/s, iops=111 , runt= 20005msec
    slat (usec): min=8 , max=312 , avg=35.66, stdev=21.26
    clat (usec): min=487 , max=68000 , avg=8957.66, stdev=4331.27
     lat (usec): min=528 , max=68015 , avg=8995.32, stdev=4332.05
    clat percentiles (usec):
     |  1.00th=[ 3440],  5.00th=[ 4512], 10.00th=[ 5024], 20.00th=[ 5920],
     | 30.00th=[ 6816], 40.00th=[ 7776], 50.00th=[ 8640], 60.00th=[ 9536],
     | 70.00th=[10432], 80.00th=[11200], 90.00th=[12096], 95.00th=[12864],
     | 99.00th=[27264], 99.50th=[36608], 99.90th=[52992], 99.95th=[60160],
     | 99.99th=[68096]
    bw (KB/s)  : min=  285, max=  503, per=99.99%, avg=443.95, stdev=49.29
    lat (usec) : 500=0.04%
    lat (msec) : 2=0.18%, 4=1.62%, 10=64.37%, 20=32.07%, 50=1.57%
    lat (msec) : 100=0.13%
  cpu          : usr=0.11%, sys=0.61%, ctx=2230, majf=0, minf=21
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued    : total=r=2223/w=0/d=0, short=r=0/w=0/d=0

Run status group 0 (all jobs):
   READ: io=8892KB, aggrb=444KB/s, minb=444KB/s, maxb=444KB/s, mint=20005msec, maxt=20005msec

Disk stats (read/write):
  vda: ios=2197/2, merge=0/7, ticks=19630/103, in_queue=19728, util=98.76%

Холодный кэш

monkey ~ # fio -readonly -name iops -rw=randread -bs=4096 -runtime=20 -iodepth 1 -filename /dev/vda -ioengine libaio -direct=1
iops: (g=0): rw=randread, bs=4K-4K/4K-4K, ioengine=libaio, iodepth=1
fio 2.0.7
Starting 1 process
Jobs: 1 (f=1): [r] [95.2% done] [452K/0K /s] [110 /0  iops] [eta 00m:01s]
iops: (groupid=0, jobs=1): err= 0: pid=1497
  read : io=8436.0KB, bw=431901 B/s, iops=105 , runt= 20001msec
    slat (usec): min=8 , max=70032 , avg=59.42, stdev=1524.52
    clat (usec): min=225 , max=133986 , avg=9419.83, stdev=5905.45
     lat (usec): min=289 , max=134035 , avg=9480.52, stdev=6126.76
    clat percentiles (msec):
     |  1.00th=[    3],  5.00th=[    5], 10.00th=[    6], 20.00th=[    7],
     | 30.00th=[    8], 40.00th=[    9], 50.00th=[    9], 60.00th=[   10],
     | 70.00th=[   11], 80.00th=[   12], 90.00th=[   13], 95.00th=[   14],
     | 99.00th=[   28], 99.50th=[   43], 99.90th=[   64], 99.95th=[  126],
     | 99.99th=[  135]
    bw (KB/s)  : min=  246, max=  502, per=100.00%, avg=421.10, stdev=63.38
    lat (usec) : 250=0.09%, 500=0.33%, 750=0.05%
    lat (msec) : 2=0.05%, 4=1.38%, 10=61.21%, 20=34.90%, 50=1.71%
    lat (msec) : 100=0.19%, 250=0.09%
  cpu          : usr=0.07%, sys=0.76%, ctx=2116, majf=0, minf=21
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued    : total=r=2109/w=0/d=0, short=r=0/w=0/d=0

Run status group 0 (all jobs):
   READ: io=8436KB, aggrb=421KB/s, minb=421KB/s, maxb=421KB/s, mint=20001msec, maxt=20001msec

Disk stats (read/write):
  vda: ios=2139/2, merge=1/4, ticks=20365/732, in_queue=21067, util=98.67%

Горячий кэш

monkey ~ # fio -readonly -name iops -rw=randread -bs=4096 -runtime=20 -iodepth 1 -filename /dev/vda -ioengine libaio -direct=1
iops: (g=0): rw=randread, bs=4K-4K/4K-4K, ioengine=libaio, iodepth=1
fio 2.0.7
Starting 1 process
Jobs: 1 (f=1): [r] [100.0% done] [426K/0K /s] [104 /0  iops] [eta 00m:00s]
iops: (groupid=0, jobs=1): err= 0: pid=1502
  read : io=16912KB, bw=865634 B/s, iops=211 , runt= 20006msec
    slat (usec): min=7 , max=163 , avg=19.44, stdev=15.56
    clat (usec): min=172 , max=105321 , avg=4708.36, stdev=5534.23
     lat (usec): min=206 , max=105333 , avg=4728.79, stdev=5540.49
    clat percentiles (usec):
     |  1.00th=[  203],  5.00th=[  211], 10.00th=[  221], 20.00th=[  231],
     | 30.00th=[  241], 40.00th=[  258], 50.00th=[ 2384], 60.00th=[ 6176],
     | 70.00th=[ 7968], 80.00th=[ 9664], 90.00th=[11328], 95.00th=[12352],
     | 99.00th=[18816], 99.50th=[25216], 99.90th=[51968], 99.95th=[57088],
     | 99.99th=[104960]
    bw (KB/s)  : min=  302, max=13928, per=100.00%, avg=854.87, stdev=2191.98
    lat (usec) : 250=34.08%, 500=15.80%
    lat (msec) : 2=0.05%, 4=0.76%, 10=31.86%, 20=16.60%, 50=0.73%
    lat (msec) : 100=0.09%, 250=0.02%
  cpu          : usr=0.18%, sys=0.66%, ctx=4238, majf=0, minf=21
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued    : total=r=4228/w=0/d=0, short=r=0/w=0/d=0

Run status group 0 (all jobs):
   READ: io=16912KB, aggrb=845KB/s, minb=845KB/s, maxb=845KB/s, mint=20006msec, maxt=20006msec

Disk stats (read/write):
  vda: ios=4205/2, merge=0/7, ticks=19509/68, in_queue=19577, util=98.09%