€•X@      Œsphinx.addnodes”Œdocument”“”)”}”(Œ	rawsource”Œ ”Œchildren”]”(Œtranslations”ŒLanguagesNode”“”)”}”(hhh]”(h Œpending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ
attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ	refdomain”Œstd”Œreftype”Œdoc”Œ	reftarget”Œ7/translations/zh_CN/admin-guide/device-mapper/unstriped”Œmodname”NŒ	classname”NŒrefexplicit”ˆuŒtagname”hhhubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ7/translations/zh_TW/admin-guide/device-mapper/unstriped”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ7/translations/it_IT/admin-guide/device-mapper/unstriped”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ7/translations/ja_JP/admin-guide/device-mapper/unstriped”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ7/translations/ko_KR/admin-guide/device-mapper/unstriped”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ7/translations/sp_SP/admin-guide/device-mapper/unstriped”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒ Device-mapper "unstriped" target”h]”hŒ$Device-mapper â€œunstripedâ€ target”…””}”(hh¨hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hh£hžhhŸŒQ/var/lib/git/docbuild/linux/Documentation/admin-guide/device-mapper/unstriped.rst”h Kubh¢)”}”(hhh]”(h§)”}”(hŒIntroduction”h]”hŒIntroduction”…””}”(hhºhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hh·hžhhŸh¶h KubhŒ	paragraph”“”)”}”(hX  The device-mapper "unstriped" target provides a transparent mechanism to
unstripe a device-mapper "striped" target to access the underlying disks
without having to touch the true backing block-device.  It can also be
used to unstripe a hardware RAID-0 to access backing disks.”h]”hX  The device-mapper â€œunstripedâ€ target provides a transparent mechanism to
unstripe a device-mapper â€œstripedâ€ target to access the underlying disks
without having to touch the true backing block-device.  It can also be
used to unstripe a hardware RAID-0 to access backing disks.”…””}”(hhÊhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Khh·hžhubhÉ)”}”(hŒKParameters:
<number of stripes> <chunk size> <stripe #> <dev_path> <offset>”h]”hŒKParameters:
<number of stripes> <chunk size> <stripe #> <dev_path> <offset>”…””}”(hhØhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Khh·hžhubhŒdefinition_list”“”)”}”(hhh]”(hŒdefinition_list_item”“”)”}”(hŒ9<number of stripes>
The number of stripes in the RAID 0.
”h]”(hŒterm”“”)”}”(hŒ<number of stripes>”h]”hŒ<number of stripes>”…””}”(hhóhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hñhŸh¶h KhhíubhŒ
definition”“”)”}”(hhh]”hÉ)”}”(hŒ$The number of stripes in the RAID 0.”h]”hŒ$The number of stripes in the RAID 0.”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Khj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hhíubeh}”(h]”h ]”h"]”h$]”h&]”uh1hëhŸh¶h Khhèubhì)”}”(hŒ?<chunk size>
The amount of 512B sectors in the chunk striping.
”h]”(hò)”}”(hŒ<chunk size>”h]”hŒ<chunk size>”…””}”(hj$  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hñhŸh¶h Khj   ubj  )”}”(hhh]”hÉ)”}”(hŒ1The amount of 512B sectors in the chunk striping.”h]”hŒ1The amount of 512B sectors in the chunk striping.”…””}”(hj5  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Khj2  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hj   ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hëhŸh¶h Khhèhžhubhì)”}”(hŒ2<dev_path>
The block device you wish to unstripe.
”h]”(hò)”}”(hŒ
<dev_path>”h]”hŒ
<dev_path>”…””}”(hjS  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hñhŸh¶h KhjO  ubj  )”}”(hhh]”hÉ)”}”(hŒ&The block device you wish to unstripe.”h]”hŒ&The block device you wish to unstripe.”…””}”(hjd  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Khja  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hjO  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hëhŸh¶h Khhèhžhubhì)”}”(hŒ‚<stripe #>
The stripe number within the device that corresponds to physical
drive you wish to unstripe.  This must be 0 indexed.

”h]”(hò)”}”(hŒ
<stripe #>”h]”hŒ
<stripe #>”…””}”(hj‚  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hñhŸh¶h Khj~  ubj  )”}”(hhh]”hÉ)”}”(hŒuThe stripe number within the device that corresponds to physical
drive you wish to unstripe.  This must be 0 indexed.”h]”hŒuThe stripe number within the device that corresponds to physical
drive you wish to unstripe.  This must be 0 indexed.”…””}”(hj“  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Khj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hj~  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hëhŸh¶h Khhèhžhubeh}”(h]”h ]”h"]”h$]”h&]”uh1hæhh·hžhhŸh¶h Nubeh}”(h]”Œintroduction”ah ]”h"]”Œintroduction”ah$]”h&]”uh1h¡hh£hžhhŸh¶h Kubh¢)”}”(hhh]”(h§)”}”(hŒWhy use this module?”h]”hŒWhy use this module?”…””}”(hj¾  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj»  hžhhŸh¶h Kubh¢)”}”(hhh]”(h§)”}”(hŒ+An example of undoing an existing dm-stripe”h]”hŒ+An example of undoing an existing dm-stripe”…””}”(hjÏ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjÌ  hžhhŸh¶h K"ubhÉ)”}”(hXy  This small bash script will setup 4 loop devices and use the existing
striped target to combine the 4 devices into one.  It then will use
the unstriped target on top of the striped device to access the
individual backing loop devices.  We write data to the newly exposed
unstriped devices and verify the data written matches the correct
underlying device on the striped array::”h]”hXx  This small bash script will setup 4 loop devices and use the existing
striped target to combine the 4 devices into one.  It then will use
the unstriped target on top of the striped device to access the
individual backing loop devices.  We write data to the newly exposed
unstriped devices and verify the data written matches the correct
underlying device on the striped array:”…””}”(hjÝ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K$hjÌ  hžhubhŒliteral_block”“”)”}”(hX„  #!/bin/bash

MEMBER_SIZE=$((128 * 1024 * 1024))
NUM=4
SEQ_END=$((${NUM}-1))
CHUNK=256
BS=4096

RAID_SIZE=$((${MEMBER_SIZE}*${NUM}/512))
DM_PARMS="0 ${RAID_SIZE} striped ${NUM} ${CHUNK}"
COUNT=$((${MEMBER_SIZE} / ${BS}))

for i in $(seq 0 ${SEQ_END}); do
  dd if=/dev/zero of=member-${i} bs=${MEMBER_SIZE} count=1 oflag=direct
  losetup /dev/loop${i} member-${i}
  DM_PARMS+=" /dev/loop${i} 0"
done

echo $DM_PARMS | dmsetup create raid0
for i in $(seq 0 ${SEQ_END}); do
  echo "0 1 unstriped ${NUM} ${CHUNK} ${i} /dev/mapper/raid0 0" | dmsetup create set-${i}
done;

for i in $(seq 0 ${SEQ_END}); do
  dd if=/dev/urandom of=/dev/mapper/set-${i} bs=${BS} count=${COUNT} oflag=direct
  diff /dev/mapper/set-${i} member-${i}
done;

for i in $(seq 0 ${SEQ_END}); do
  dmsetup remove set-${i}
done

dmsetup remove raid0

for i in $(seq 0 ${SEQ_END}); do
  losetup -d /dev/loop${i}
  rm -f member-${i}
done”h]”hX„  #!/bin/bash

MEMBER_SIZE=$((128 * 1024 * 1024))
NUM=4
SEQ_END=$((${NUM}-1))
CHUNK=256
BS=4096

RAID_SIZE=$((${MEMBER_SIZE}*${NUM}/512))
DM_PARMS="0 ${RAID_SIZE} striped ${NUM} ${CHUNK}"
COUNT=$((${MEMBER_SIZE} / ${BS}))

for i in $(seq 0 ${SEQ_END}); do
  dd if=/dev/zero of=member-${i} bs=${MEMBER_SIZE} count=1 oflag=direct
  losetup /dev/loop${i} member-${i}
  DM_PARMS+=" /dev/loop${i} 0"
done

echo $DM_PARMS | dmsetup create raid0
for i in $(seq 0 ${SEQ_END}); do
  echo "0 1 unstriped ${NUM} ${CHUNK} ${i} /dev/mapper/raid0 0" | dmsetup create set-${i}
done;

for i in $(seq 0 ${SEQ_END}); do
  dd if=/dev/urandom of=/dev/mapper/set-${i} bs=${BS} count=${COUNT} oflag=direct
  diff /dev/mapper/set-${i} member-${i}
done;

for i in $(seq 0 ${SEQ_END}); do
  dmsetup remove set-${i}
done

dmsetup remove raid0

for i in $(seq 0 ${SEQ_END}); do
  losetup -d /dev/loop${i}
  rm -f member-${i}
done”…””}”hjí  sbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1jë  hŸh¶h K+hjÌ  hžhubeh}”(h]”Œ+an-example-of-undoing-an-existing-dm-stripe”ah ]”h"]”Œ+an example of undoing an existing dm-stripe”ah$]”h&]”uh1h¡hj»  hžhhŸh¶h K"ubh¢)”}”(hhh]”(h§)”}”(hŒAnother example”h]”hŒAnother example”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj  hžhhŸh¶h KSubhÉ)”}”(hŒèIntel NVMe drives contain two cores on the physical device.
Each core of the drive has segregated access to its LBA range.
The current LBA model has a RAID 0 128k chunk on each core, resulting
in a 256k stripe across the two cores::”h]”hŒçIntel NVMe drives contain two cores on the physical device.
Each core of the drive has segregated access to its LBA range.
The current LBA model has a RAID 0 128k chunk on each core, resulting
in a 256k stripe across the two cores:”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KUhj  hžhubjì  )”}”(hŒz Core 0:       Core 1:
__________    __________
| LBA 512|    | LBA 768|
| LBA 0  |    | LBA 256|
----------    ----------”h]”hŒz Core 0:       Core 1:
__________    __________
| LBA 512|    | LBA 768|
| LBA 0  |    | LBA 256|
----------    ----------”…””}”hj$  sbah}”(h]”h ]”h"]”h$]”h&]”jû  jü  uh1jë  hŸh¶h KZhj  hžhubhÉ)”}”(hX¯  The purpose of this unstriping is to provide better QoS in noisy
neighbor environments. When two partitions are created on the
aggregate drive without this unstriping, reads on one partition
can affect writes on another partition.  This is because the partitions
are striped across the two cores.  When we unstripe this hardware RAID 0
and make partitions on each new exposed device the two partitions are now
physically separated.”h]”hX¯  The purpose of this unstriping is to provide better QoS in noisy
neighbor environments. When two partitions are created on the
aggregate drive without this unstriping, reads on one partition
can affect writes on another partition.  This is because the partitions
are striped across the two cores.  When we unstripe this hardware RAID 0
and make partitions on each new exposed device the two partitions are now
physically separated.”…””}”(hj2  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K`hj  hžhubhÉ)”}”(hX  With the dm-unstriped target we're able to segregate an fio script that
has read and write jobs that are independent of each other.  Compared to
when we run the test on a combined drive with partitions, we were able
to get a 92% reduction in read latency using this device mapper target.”h]”hX!  With the dm-unstriped target weâ€™re able to segregate an fio script that
has read and write jobs that are independent of each other.  Compared to
when we run the test on a combined drive with partitions, we were able
to get a 92% reduction in read latency using this device mapper target.”…””}”(hj@  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Khhj  hžhubeh}”(h]”Œanother-example”ah ]”h"]”Œanother example”ah$]”h&]”uh1h¡hj»  hžhhŸh¶h KSubeh}”(h]”Œwhy-use-this-module”ah ]”h"]”Œwhy use this module?”ah$]”h&]”uh1h¡hh£hžhhŸh¶h Kubh¢)”}”(hhh]”(h§)”}”(hŒExample dmsetup usage”h]”hŒExample dmsetup usage”…””}”(hja  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj^  hžhhŸh¶h Koubh¢)”}”(hhh]”(h§)”}”(hŒ6unstriped on top of Intel NVMe device that has 2 cores”h]”hŒ6unstriped on top of Intel NVMe device that has 2 cores”…””}”(hjr  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjo  hžhhŸh¶h Krubjì  )”}”(hŒdmsetup create nvmset0 --table '0 512 unstriped 2 256 0 /dev/nvme0n1 0'
dmsetup create nvmset1 --table '0 512 unstriped 2 256 1 /dev/nvme0n1 0'”h]”hŒdmsetup create nvmset0 --table '0 512 unstriped 2 256 0 /dev/nvme0n1 0'
dmsetup create nvmset1 --table '0 512 unstriped 2 256 1 /dev/nvme0n1 0'”…””}”hj€  sbah}”(h]”h ]”h"]”h$]”h&]”jû  jü  uh1jë  hŸh¶h Kvhjo  hžhubhÉ)”}”(hŒPThere will now be two devices that expose Intel NVMe core 0 and 1
respectively::”h]”hŒOThere will now be two devices that expose Intel NVMe core 0 and 1
respectively:”…””}”(hjŽ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Kyhjo  hžhubjì  )”}”(hŒ'/dev/mapper/nvmset0
/dev/mapper/nvmset1”h]”hŒ'/dev/mapper/nvmset0
/dev/mapper/nvmset1”…””}”hjœ  sbah}”(h]”h ]”h"]”h$]”h&]”jû  jü  uh1jë  hŸh¶h K|hjo  hžhubeh}”(h]”Œ6unstriped-on-top-of-intel-nvme-device-that-has-2-cores”ah ]”h"]”Œ6unstriped on top of intel nvme device that has 2 cores”ah$]”h&]”uh1h¡hj^  hžhhŸh¶h Krubh¢)”}”(hhh]”(h§)”}”(hŒ?unstriped on top of striped with 4 drives using 128K chunk size”h]”hŒ?unstriped on top of striped with 4 drives using 128K chunk size”…””}”(hjµ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj²  hžhhŸh¶h K€ubjì  )”}”(hXG  dmsetup create raid_disk0 --table '0 512 unstriped 4 256 0 /dev/mapper/striped 0'
dmsetup create raid_disk1 --table '0 512 unstriped 4 256 1 /dev/mapper/striped 0'
dmsetup create raid_disk2 --table '0 512 unstriped 4 256 2 /dev/mapper/striped 0'
dmsetup create raid_disk3 --table '0 512 unstriped 4 256 3 /dev/mapper/striped 0'”h]”hXG  dmsetup create raid_disk0 --table '0 512 unstriped 4 256 0 /dev/mapper/striped 0'
dmsetup create raid_disk1 --table '0 512 unstriped 4 256 1 /dev/mapper/striped 0'
dmsetup create raid_disk2 --table '0 512 unstriped 4 256 2 /dev/mapper/striped 0'
dmsetup create raid_disk3 --table '0 512 unstriped 4 256 3 /dev/mapper/striped 0'”…””}”hjÃ  sbah}”(h]”h ]”h"]”h$]”h&]”jû  jü  uh1jë  hŸh¶h K„hj²  hžhubeh}”(h]”Œ?unstriped-on-top-of-striped-with-4-drives-using-128k-chunk-size”ah ]”h"]”Œ?unstriped on top of striped with 4 drives using 128k chunk size”ah$]”h&]”uh1h¡hj^  hžhhŸh¶h K€ubeh}”(h]”Œexample-dmsetup-usage”ah ]”h"]”Œexample dmsetup usage”ah$]”h&]”uh1h¡hh£hžhhŸh¶h Koubeh}”(h]”Œdevice-mapper-unstriped-target”ah ]”h"]”Œ device-mapper "unstriped" target”ah$]”h&]”uh1h¡hhhžhhŸh¶h Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”h¶uh1hŒcurrent_source”NŒcurrent_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(h¦NŒ	generator”NŒ	datestamp”NŒsource_link”NŒ
source_url”NŒtoc_backlinks”Œentry”Œfootnote_backlinks”KŒsectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒstrip_classes”NŒreport_level”KŒ
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