Inhaltsverzeichnis

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Überprüfen der Disk-I/O

Leitfrage: Festplatten, Festplatten-RAIDs, Software-RAIDs oder Hardware-RAIDs - was braucht man für welchen Zweck?

Frage: Hardware oder Software-RAID

Neben der Fragen der Performance, zählt für mich noch das Argument der Wiederherstellung im Disasterfall: Wenn der Hardware-Controller ausfällt braucht man (meines Wissens nach) einen identischen, zumindest gleicher Bauart und neuer RAID-Controller, damit auf dem neuen RAID-Controller die Plattenzusammenstellung wieder erkannt wird. Beim Software-RAID muss man nur einen neuen Computer/Mainboard finden und alle relevanten Platten einen Anschluss finden. Und man würde natürlich auf SATA statt SAS setzen, was es billiger macht und man flexibler ist.

Test zwischen Hard- und Software-RAID 5

Ich teste auf einem System zwei RAID5: einmal 3 Festplatten auf einem Hardware-RAID, einmal 3 Festplatten in einem Software-RAID

Testbedingungen

Eigenschaft Software-RAID Hardware-RAID
Art RAID5 RAID5
controller mdadm (DISKs als JBOD von 3ware durchgereicht) 3ware 9650SE
Anzahl HDDs 3 3
Typ HDDs 3×7200 RPM Barracuda-ES, baugleich 3x7200RPM Barracuda-ES, 2 baugleich, 1 kleiner und älter
Zeit morgens 7 Uhr, nahezu kein Traffic morgens 7 Uhr, nahezu kein Traffic
load im laufenden Betrieb, sonst kein Zugriff im laufenden Betrieb, Zugriff von 5 VMs

Ergebnisse hdparm

Software-RAID
# hdparm -t -T /dev/md/storage

/dev/md/storage:
 Timing cached reads:   17692 MB in  2.00 seconds = 8854.64 MB/sec
 Timing buffered disk reads: 772 MB in  3.01 seconds = 256.84 MB/sec
Hardware-RAID
# hdparm -t -T /dev/sda

/dev/sda:
 Timing cached reads:   17066 MB in  2.00 seconds = 8540.70 MB/sec
 Timing buffered disk reads: 586 MB in  3.00 seconds = 195.14 MB/sec

Ergebnisse fio

# aptitude install fio 
Konfiguration fio

Diese Konfiguration wurde einfach von hier übernommen, ohne nachzudenken, ob das I/O dem des linuxmuster.net Server entspricht oder nicht.

Das directory muss für die jeweilige Konfiguration in einem Verzeichnis auf dem Dateisystem des zu testenden Systems liegen.

# fio --output four-threads-randio.fio.log four-threads-randio.fio 
# fio --output 3ware-four-threads-randio.fio.log 3ware-four-threads-randio.fio

++++ Konfiguration aufklappen |

# cat four-threads-randio.fio
; Four threads, two query, two writers.

[global]
rw=randread
size=256m
directory=./fio-testing-data
ioengine=libaio
iodepth=4
invalidate=1
direct=1

[bgwriter]
rw=randwrite
iodepth=32

[queryA]
iodepth=1
ioengine=mmap
direct=0
thinktime=3

[queryB]
iodepth=1
ioengine=mmap
direct=0
thinktime=5

[bgupdater]
rw=randrw
iodepth=16
thinktime=40
size=32m

++++

Software-RAID

++++ Gesamtes Ergebnis-LOG aufklappen |

# cat four-threads-randio.fio.log

bgwriter: (g=0): rw=randwrite, bs=4K-4K/4K-4K, ioengine=libaio, iodepth=32
queryA: (g=0): rw=randread, bs=4K-4K/4K-4K, ioengine=mmap, iodepth=1
queryB: (g=0): rw=randread, bs=4K-4K/4K-4K, ioengine=mmap, iodepth=1
bgupdater: (g=0): rw=randrw, bs=4K-4K/4K-4K, ioengine=libaio, iodepth=16
fio 1.59
Starting 4 processes

bgwriter: (groupid=0, jobs=1): err= 0: pid=27437
  write: io=262144KB, bw=2263.4KB/s, iops=565 , runt=115822msec
    slat (usec): min=3 , max=118225 , avg=39.25, stdev=1290.65
    clat (usec): min=156 , max=1515.7K, avg=56502.06, stdev=61108.65
     lat (usec): min=163 , max=1515.7K, avg=56541.80, stdev=61120.94
    bw (KB/s) : min=    0, max= 4359, per=83.34%, avg=2002.68, stdev=811.04
  cpu          : usr=0.84%, sys=3.49%, ctx=63684, majf=0, minf=20
  IO depths    : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=100.0%, >=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=0.1%, 64=0.0%, >=64=0.0%
     issued r/w/d: total=0/65536/0, short=0/0/0
     lat (usec): 250=0.07%, 500=0.73%, 750=0.62%, 1000=0.63%
     lat (msec): 2=2.62%, 4=4.60%, 10=6.84%, 20=8.96%, 50=25.22%
     lat (msec): 100=37.08%, 250=12.07%, 500=0.21%, 750=0.17%, 1000=0.09%
     lat (msec): 2000=0.08%
queryA: (groupid=0, jobs=1): err= 0: pid=27438
  read : io=262144KB, bw=643708 B/s, iops=157 , runt=417014msec
    clat (usec): min=176 , max=200425 , avg=6287.15, stdev=11708.44
     lat (usec): min=176 , max=200425 , avg=6287.50, stdev=11708.43
    bw (KB/s) : min=   42, max= 3548, per=49.00%, avg=635.08, stdev=363.95
  cpu          : usr=0.03%, sys=0.98%, ctx=131137, majf=65536, minf=30
  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 r/w/d: total=65536/0/0, short=0/0/0
     lat (usec): 250=0.93%, 500=17.14%, 750=5.39%, 1000=0.86%
     lat (msec): 2=6.15%, 4=15.67%, 10=46.72%, 20=4.41%, 50=0.99%
     lat (msec): 100=1.34%, 250=0.38%
queryB: (groupid=0, jobs=1): err= 0: pid=27439
  read : io=262144KB, bw=646142 B/s, iops=157 , runt=415443msec
    clat (usec): min=160 , max=271656 , avg=6261.13, stdev=11846.33
     lat (usec): min=160 , max=271657 , avg=6261.49, stdev=11846.33
    bw (KB/s) : min=   37, max= 2801, per=49.59%, avg=642.66, stdev=363.18
  cpu          : usr=0.02%, sys=1.00%, ctx=131139, majf=65536, minf=29
  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 r/w/d: total=65536/0/0, short=0/0/0
     lat (usec): 250=0.75%, 500=17.31%, 750=5.46%, 1000=1.05%
     lat (msec): 2=6.20%, 4=15.78%, 10=46.44%, 20=4.26%, 50=1.01%
     lat (msec): 100=1.32%, 250=0.41%, 500=0.01%
bgupdater: (groupid=0, jobs=1): err= 0: pid=27440
  read : io=16548KB, bw=772410 B/s, iops=188 , runt= 21938msec
    slat (usec): min=6 , max=62538 , avg=30.38, stdev=972.10
    clat (usec): min=150 , max=248703 , avg=34749.50, stdev=34677.60
     lat (usec): min=166 , max=248728 , avg=34780.21, stdev=34677.13
    bw (KB/s) : min=    0, max= 1344, per=53.27%, avg=690.34, stdev=253.09
  write: io=16220KB, bw=757100 B/s, iops=184 , runt= 21938msec
    slat (usec): min=5 , max=67015 , avg=59.93, stdev=1725.22
    clat (usec): min=164 , max=700093 , avg=50753.48, stdev=45899.73
     lat (usec): min=178 , max=700105 , avg=50813.75, stdev=45948.04
    bw (KB/s) : min=  541, max= 1648, per=30.77%, avg=739.43, stdev=174.52
  cpu          : usr=0.51%, sys=1.51%, ctx=14239, majf=0, minf=23
  IO depths    : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=99.8%, 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=0.1%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued r/w/d: total=4137/4055/0, short=0/0/0
     lat (usec): 250=0.24%, 500=1.71%, 750=1.28%, 1000=1.27%
     lat (msec): 2=6.07%, 4=8.07%, 10=12.06%, 20=9.80%, 50=20.98%
     lat (msec): 100=29.98%, 250=8.41%, 500=0.09%, 750=0.04%

Run status group 0 (all jobs):
   READ: io=540836KB, aggrb=1296KB/s, minb=643KB/s, maxb=772KB/s, mint=21938msec, maxt=417014msec
  WRITE: io=278364KB, aggrb=2403KB/s, minb=757KB/s, maxb=2317KB/s, mint=21938msec, maxt=115822msec

Disk stats (read/write):
  md127: ios=135165/69672, merge=0/0, ticks=0/0, in_queue=0, util=0.00%, aggrios=68188/46436, aggrmerge=9/32, aggrticks=1253285/593384, aggrin_queue=1846674, aggrutil=66.60%
    sdb: ios=68242/46501, merge=0/43, ticks=1260148/592240, in_queue=1852372, util=66.60%
    sdd: ios=68168/46420, merge=0/41, ticks=1250500/590996, in_queue=1841512, util=66.05%
    sde: ios=68155/46387, merge=28/12, ticks=1249208/596916, in_queue=1846140, util=66.47%

++++

Hardware-RAID

++++ Gesamtes Ergebnis-LOG aufklappen |

# cat 3ware-four-threads-randio.fio.log

bgwriter: (g=0): rw=randwrite, bs=4K-4K/4K-4K, ioengine=libaio, iodepth=32
queryA: (g=0): rw=randread, bs=4K-4K/4K-4K, ioengine=mmap, iodepth=1
queryB: (g=0): rw=randread, bs=4K-4K/4K-4K, ioengine=mmap, iodepth=1
bgupdater: (g=0): rw=randrw, bs=4K-4K/4K-4K, ioengine=libaio, iodepth=16
fio 1.59
Starting 4 processes

bgwriter: (groupid=0, jobs=1): err= 0: pid=4990
  write: io=262144KB, bw=563087 B/s, iops=137 , runt=476721msec
    slat (usec): min=5 , max=3312.1K, avg=682.18, stdev=42345.18
    clat (usec): min=65 , max=8143.4K, avg=231980.82, stdev=861214.70
     lat (usec): min=77 , max=8143.4K, avg=232663.24, stdev=862096.66
    bw (KB/s) : min=    1, max= 3411, per=103.74%, avg=605.85, stdev=659.98
  cpu          : usr=0.02%, sys=0.26%, ctx=60906, majf=0, minf=20
  IO depths    : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=100.0%, >=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=0.1%, 64=0.0%, >=64=0.0%
     issued r/w/d: total=0/65536/0, short=0/0/0
     lat (usec): 100=0.01%, 500=0.37%, 750=0.32%, 1000=0.32%
     lat (msec): 2=1.32%, 4=85.57%, 10=2.38%, 20=0.72%, 50=0.22%
     lat (msec): 100=0.40%, 250=0.52%, 500=0.30%, 750=0.24%, 1000=0.15%
     lat (msec): 2000=0.68%, >=2000=6.47%
queryA: (groupid=0, jobs=1): err= 0: pid=4991
  read : io=262144KB, bw=315841 B/s, iops=77 , runt=849905msec
    clat (usec): min=65 , max=1146.6K, avg=12892.38, stdev=38584.22
     lat (usec): min=65 , max=1146.6K, avg=12892.73, stdev=38584.22
    bw (KB/s) : min=    5, max= 2142, per=52.53%, avg=334.10, stdev=293.16
  cpu          : usr=0.01%, sys=0.49%, ctx=131093, majf=65536, minf=30
  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 r/w/d: total=65536/0/0, short=0/0/0
     lat (usec): 100=0.74%, 250=5.76%, 500=7.66%, 750=2.81%, 1000=0.64%
     lat (msec): 2=2.88%, 4=12.95%, 10=45.56%, 20=13.32%, 50=3.72%
     lat (msec): 100=1.65%, 250=1.63%, 500=0.60%, 750=0.08%, 1000=0.01%
     lat (msec): 2000=0.01%
queryB: (groupid=0, jobs=1): err= 0: pid=4992
  read : io=262144KB, bw=316713 B/s, iops=77 , runt=847565msec
    clat (usec): min=62 , max=1453.9K, avg=12854.74, stdev=40260.59
     lat (usec): min=62 , max=1453.9K, avg=12855.10, stdev=40260.59
    bw (KB/s) : min=    3, max= 1204, per=53.04%, avg=337.32, stdev=302.66
  cpu          : usr=0.01%, sys=0.48%, ctx=131109, majf=65536, minf=29
  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 r/w/d: total=65536/0/0, short=0/0/0
     lat (usec): 100=0.96%, 250=7.71%, 500=7.86%, 750=2.65%, 1000=0.63%
     lat (msec): 2=2.80%, 4=12.47%, 10=44.34%, 20=13.24%, 50=3.38%
     lat (msec): 100=1.58%, 250=1.69%, 500=0.59%, 750=0.08%, 1000=0.02%
     lat (msec): 2000=0.01%
bgupdater: (groupid=0, jobs=1): err= 0: pid=4993
  read : io=16296KB, bw=81036 B/s, iops=19 , runt=205921msec
    slat (usec): min=7 , max=3201.3K, avg=4739.56, stdev=104796.65
    clat (usec): min=2 , max=2752.5K, avg=98666.26, stdev=215133.50
     lat (usec): min=78 , max=3201.3K, avg=103406.16, stdev=237364.57
    bw (KB/s) : min=    0, max= 5928, per=29.74%, avg=189.14, stdev=623.76
  write: io=16472KB, bw=81911 B/s, iops=19 , runt=205921msec
    slat (usec): min=8 , max=3011.1K, avg=1733.96, stdev=63925.62
    clat (usec): min=65 , max=8140.2K, avg=695273.75, stdev=1395565.63
     lat (usec): min=74 , max=8140.2K, avg=697008.03, stdev=1396181.47
    bw (KB/s) : min=    0, max= 6248, per=34.52%, avg=201.62, stdev=754.72
  cpu          : usr=0.02%, sys=0.15%, ctx=13742, majf=0, minf=23
  IO depths    : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=99.8%, 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=0.1%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued r/w/d: total=4074/4118/0, short=0/0/0
     lat (usec): 4=0.06%, 100=7.52%, 250=18.26%, 500=7.17%, 750=1.97%
     lat (usec): 1000=1.00%
     lat (msec): 2=2.25%, 4=8.94%, 10=6.49%, 20=5.70%, 50=7.40%
     lat (msec): 100=6.25%, 250=8.96%, 500=4.14%, 750=1.32%, 1000=0.67%
     lat (msec): 2000=2.94%, >=2000=8.97%

Run status group 0 (all jobs):
   READ: io=540584KB, aggrb=636KB/s, minb=81KB/s, maxb=316KB/s, mint=205921msec, maxt=849905msec
  WRITE: io=278616KB, aggrb=584KB/s, minb=81KB/s, maxb=563KB/s, mint=205921msec, maxt=476721msec

Disk stats (read/write):
  dm-2: ios=135457/71309, merge=0/0, ticks=2052000/18297432, in_queue=20349460, util=100.00%, aggrios=146894/83854, aggrmerge=33536/40266, aggrticks=2219656/22239272, aggrin_queue=24461388, aggrutil=100.00%
    sda: ios=146894/83854, merge=33536/40266, ticks=2219656/22239272, in_queue=24461388, util=100.00%

++++

Unterschiede anzeigen

Links: Hardware-RAID, Rechts: Software-RAID ++++ Unterschiede komplett aufklappen |

diff -y *.log | less -S
bgwriter: (g=0): rw=randwrite, bs=4K-4K/4K-4K, ioengine=libai   bgwriter: (g=0): rw=randwrite, bs=4K-4K/4K-4K, ioengine=libai
queryA: (g=0): rw=randread, bs=4K-4K/4K-4K, ioengine=mmap, io   queryA: (g=0): rw=randread, bs=4K-4K/4K-4K, ioengine=mmap, io
queryB: (g=0): rw=randread, bs=4K-4K/4K-4K, ioengine=mmap, io   queryB: (g=0): rw=randread, bs=4K-4K/4K-4K, ioengine=mmap, io
bgupdater: (g=0): rw=randrw, bs=4K-4K/4K-4K, ioengine=libaio,   bgupdater: (g=0): rw=randrw, bs=4K-4K/4K-4K, ioengine=libaio,
fio 1.59                                                        fio 1.59
Starting 4 processes                                            Starting 4 processes

bgwriter: (groupid=0, jobs=1): err= 0: pid=4990               | bgwriter: (groupid=0, jobs=1): err= 0: pid=27437
  write: io=262144KB, bw=563087 B/s, iops=137 , runt=476721ms |   write: io=262144KB, bw=2263.4KB/s, iops=565 , runt=115822ms
    slat (usec): min=5 , max=3312.1K, avg=682.18, stdev=42345 |     slat (usec): min=3 , max=118225 , avg=39.25, stdev=1290.6
    clat (usec): min=65 , max=8143.4K, avg=231980.82, stdev=8 |     clat (usec): min=156 , max=1515.7K, avg=56502.06, stdev=6
     lat (usec): min=77 , max=8143.4K, avg=232663.24, stdev=8 |      lat (usec): min=163 , max=1515.7K, avg=56541.80, stdev=6
    bw (KB/s) : min=    1, max= 3411, per=103.74%, avg=605.85 |     bw (KB/s) : min=    0, max= 4359, per=83.34%, avg=2002.68
  cpu          : usr=0.02%, sys=0.26%, ctx=60906, majf=0, min |   cpu          : usr=0.84%, sys=3.49%, ctx=63684, majf=0, min
  IO depths    : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=     IO depths    : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%,         submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%,         complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%, 
     issued r/w/d: total=0/65536/0, short=0/0/0                      issued r/w/d: total=0/65536/0, short=0/0/0
     lat (usec): 100=0.01%, 500=0.37%, 750=0.32%, 1000=0.32%  |      lat (usec): 250=0.07%, 500=0.73%, 750=0.62%, 1000=0.63%
     lat (msec): 2=1.32%, 4=85.57%, 10=2.38%, 20=0.72%, 50=0. |      lat (msec): 2=2.62%, 4=4.60%, 10=6.84%, 20=8.96%, 50=25.
     lat (msec): 100=0.40%, 250=0.52%, 500=0.30%, 750=0.24%,  |      lat (msec): 100=37.08%, 250=12.07%, 500=0.21%, 750=0.17%
     lat (msec): 2000=0.68%, >=2000=6.47%                     |      lat (msec): 2000=0.08%
queryA: (groupid=0, jobs=1): err= 0: pid=4991                 | queryA: (groupid=0, jobs=1): err= 0: pid=27438
  read : io=262144KB, bw=315841 B/s, iops=77 , runt=849905mse |   read : io=262144KB, bw=643708 B/s, iops=157 , runt=417014ms
    clat (usec): min=65 , max=1146.6K, avg=12892.38, stdev=38 |     clat (usec): min=176 , max=200425 , avg=6287.15, stdev=11
     lat (usec): min=65 , max=1146.6K, avg=12892.73, stdev=38 |      lat (usec): min=176 , max=200425 , avg=6287.50, stdev=11
    bw (KB/s) : min=    5, max= 2142, per=52.53%, avg=334.10, |     bw (KB/s) : min=   42, max= 3548, per=49.00%, avg=635.08,
  cpu          : usr=0.01%, sys=0.49%, ctx=131093, majf=65536 |   cpu          : usr=0.03%, sys=0.98%, ctx=131137, majf=65536
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 3     IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 3
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%,         submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%,         complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 
     issued r/w/d: total=65536/0/0, short=0/0/0                      issued r/w/d: total=65536/0/0, short=0/0/0
     lat (usec): 100=0.74%, 250=5.76%, 500=7.66%, 750=2.81%,  |      lat (usec): 250=0.93%, 500=17.14%, 750=5.39%, 1000=0.86%
     lat (msec): 2=2.88%, 4=12.95%, 10=45.56%, 20=13.32%, 50= |      lat (msec): 2=6.15%, 4=15.67%, 10=46.72%, 20=4.41%, 50=0
     lat (msec): 100=1.65%, 250=1.63%, 500=0.60%, 750=0.08%,  |      lat (msec): 100=1.34%, 250=0.38%
     lat (msec): 2000=0.01%                                   | queryB: (groupid=0, jobs=1): err= 0: pid=27439
queryB: (groupid=0, jobs=1): err= 0: pid=4992                 |   read : io=262144KB, bw=646142 B/s, iops=157 , runt=415443ms
  read : io=262144KB, bw=316713 B/s, iops=77 , runt=847565mse |     clat (usec): min=160 , max=271656 , avg=6261.13, stdev=11
    clat (usec): min=62 , max=1453.9K, avg=12854.74, stdev=40 |      lat (usec): min=160 , max=271657 , avg=6261.49, stdev=11
     lat (usec): min=62 , max=1453.9K, avg=12855.10, stdev=40 |     bw (KB/s) : min=   37, max= 2801, per=49.59%, avg=642.66,
    bw (KB/s) : min=    3, max= 1204, per=53.04%, avg=337.32, |   cpu          : usr=0.02%, sys=1.00%, ctx=131139, majf=65536
  cpu          : usr=0.01%, sys=0.48%, ctx=131109, majf=65536 <
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 3     IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 3
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%,         submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%,         complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 
     issued r/w/d: total=65536/0/0, short=0/0/0                      issued r/w/d: total=65536/0/0, short=0/0/0
     lat (usec): 100=0.96%, 250=7.71%, 500=7.86%, 750=2.65%,  |      lat (usec): 250=0.75%, 500=17.31%, 750=5.46%, 1000=1.05%
     lat (msec): 2=2.80%, 4=12.47%, 10=44.34%, 20=13.24%, 50= |      lat (msec): 2=6.20%, 4=15.78%, 10=46.44%, 20=4.26%, 50=1
     lat (msec): 100=1.58%, 250=1.69%, 500=0.59%, 750=0.08%,  |      lat (msec): 100=1.32%, 250=0.41%, 500=0.01%
     lat (msec): 2000=0.01%                                   | bgupdater: (groupid=0, jobs=1): err= 0: pid=27440
bgupdater: (groupid=0, jobs=1): err= 0: pid=4993              |   read : io=16548KB, bw=772410 B/s, iops=188 , runt= 21938mse
  read : io=16296KB, bw=81036 B/s, iops=19 , runt=205921msec  |     slat (usec): min=6 , max=62538 , avg=30.38, stdev=972.10
    slat (usec): min=7 , max=3201.3K, avg=4739.56, stdev=1047 |     clat (usec): min=150 , max=248703 , avg=34749.50, stdev=3
    clat (usec): min=2 , max=2752.5K, avg=98666.26, stdev=215 |      lat (usec): min=166 , max=248728 , avg=34780.21, stdev=3
     lat (usec): min=78 , max=3201.3K, avg=103406.16, stdev=2 |     bw (KB/s) : min=    0, max= 1344, per=53.27%, avg=690.34,
    bw (KB/s) : min=    0, max= 5928, per=29.74%, avg=189.14, |   write: io=16220KB, bw=757100 B/s, iops=184 , runt= 21938mse
  write: io=16472KB, bw=81911 B/s, iops=19 , runt=205921msec  |     slat (usec): min=5 , max=67015 , avg=59.93, stdev=1725.22
    slat (usec): min=8 , max=3011.1K, avg=1733.96, stdev=6392 |     clat (usec): min=164 , max=700093 , avg=50753.48, stdev=4
    clat (usec): min=65 , max=8140.2K, avg=695273.75, stdev=1 |      lat (usec): min=178 , max=700105 , avg=50813.75, stdev=4
     lat (usec): min=74 , max=8140.2K, avg=697008.03, stdev=1 |     bw (KB/s) : min=  541, max= 1648, per=30.77%, avg=739.43,
    bw (KB/s) : min=    0, max= 6248, per=34.52%, avg=201.62, |   cpu          : usr=0.51%, sys=1.51%, ctx=14239, majf=0, min
  cpu          : usr=0.02%, sys=0.15%, ctx=13742, majf=0, min <
  IO depths    : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=99.8%, 32     IO depths    : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=99.8%, 32
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%,         submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.1%, 32=0.0%,         complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.1%, 32=0.0%, 
     issued r/w/d: total=4074/4118/0, short=0/0/0             |      issued r/w/d: total=4137/4055/0, short=0/0/0
     lat (usec): 4=0.06%, 100=7.52%, 250=18.26%, 500=7.17%, 7 |      lat (usec): 250=0.24%, 500=1.71%, 750=1.28%, 1000=1.27%
     lat (usec): 1000=1.00%                                   |      lat (msec): 2=6.07%, 4=8.07%, 10=12.06%, 20=9.80%, 50=20
     lat (msec): 2=2.25%, 4=8.94%, 10=6.49%, 20=5.70%, 50=7.4 |      lat (msec): 100=29.98%, 250=8.41%, 500=0.09%, 750=0.04%
     lat (msec): 100=6.25%, 250=8.96%, 500=4.14%, 750=1.32%,  <
     lat (msec): 2000=2.94%, >=2000=8.97%                     <

Run status group 0 (all jobs):                                  Run status group 0 (all jobs):
   READ: io=540584KB, aggrb=636KB/s, minb=81KB/s, maxb=316KB/ |    READ: io=540836KB, aggrb=1296KB/s, minb=643KB/s, maxb=772K
  WRITE: io=278616KB, aggrb=584KB/s, minb=81KB/s, maxb=563KB/ |   WRITE: io=278364KB, aggrb=2403KB/s, minb=757KB/s, maxb=2317

Disk stats (read/write):                                        Disk stats (read/write):
  dm-2: ios=135457/71309, merge=0/0, ticks=2052000/18297432,  |   md127: ios=135165/69672, merge=0/0, ticks=0/0, in_queue=0, 
    sda: ios=146894/83854, merge=33536/40266, ticks=2219656/2 |     sdb: ios=68242/46501, merge=0/43, ticks=1260148/592240, i
                                                              >     sdd: ios=68168/46420, merge=0/41, ticks=1250500/590996, i
                                                              >     sde: ios=68155/46387, merge=28/12, ticks=1249208/596916, 

++++

Fazit aus der Sicht des Software-RAIDs

Man kann auch andere ERgebnisse herauslesen, wenn man nur die Durchschnittswerte liest. Dann hat auch bei der Latenz das Software-RAID die Nase vorn.

Die CPU-Last ist beim Software-RAID immer höher: