€••€Œsphinx.addnodes”Œdocument”“”)”}”(Œ rawsource”Œ”Œchildren”]”(Œ translations”Œ LanguagesNode”“”)”}”(hhh]”(hŒ pending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ refdomain”Œstd”Œreftype”Œdoc”Œ reftarget”Œ8/translations/zh_CN/admin-guide/device-mapper/writecache”Œmodname”NŒ classname”NŒ refexplicit”ˆuŒtagname”hhh ubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ8/translations/zh_TW/admin-guide/device-mapper/writecache”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ8/translations/it_IT/admin-guide/device-mapper/writecache”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ8/translations/ja_JP/admin-guide/device-mapper/writecache”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ8/translations/ko_KR/admin-guide/device-mapper/writecache”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ8/translations/sp_SP/admin-guide/device-mapper/writecache”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h hhŒ _document”hŒsource”NŒline”NubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒWritecache target”h]”hŒWritecache target”…””}”(hh¨hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hh£hžhhŸŒR/var/lib/git/docbuild/linux/Documentation/admin-guide/device-mapper/writecache.rst”h KubhŒ paragraph”“”)”}”(hŒŸThe writecache target caches writes on persistent memory or on SSD. It doesn't cache reads because reads are supposed to be cached in page cache in normal RAM.”h]”hŒ¡The writecache target caches writes on persistent memory or on SSD. It doesn’t cache reads because reads are supposed to be cached in page cache in normal RAM.”…””}”(hh¹hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khh£hžhubh¸)”}”(hŒWhen the device is constructed, the first sector should be zeroed or the first sector should contain valid superblock from previous invocation.”h]”hŒWhen the device is constructed, the first sector should be zeroed or the first sector should contain valid superblock from previous invocation.”…””}”(hhÇhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K hh£hžhubh¸)”}”(hŒConstructor parameters:”h]”hŒConstructor parameters:”…””}”(hhÕhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K hh£hžhubhŒenumerated_list”“”)”}”(hhh]”(hŒ list_item”“”)”}”(hŒQtype of the cache device - "p" or "s" - p - persistent memory - s - SSD”h]”hŒdefinition_list”“”)”}”(hhh]”hŒdefinition_list_item”“”)”}”(hŒGtype of the cache device - "p" or "s" - p - persistent memory - s - SSD”h]”(hŒterm”“”)”}”(hŒ%type of the cache device - "p" or "s"”h]”hŒ-type of the cache device - “p†or “s—…””}”(hhûhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h KhhõubhŒ definition”“”)”}”(hhh]”hŒ bullet_list”“”)”}”(hhh]”(hé)”}”(hŒp - persistent memory”h]”h¸)”}”(hjh]”hŒp - persistent memory”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khjubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjubhé)”}”(hŒs - SSD”h]”h¸)”}”(hj,h]”hŒs - SSD”…””}”(hj.hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khj*ubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjubeh}”(h]”h ]”h"]”h$]”h&]”Œbullet”Œ-”uh1jhŸh¶h Khj ubah}”(h]”h ]”h"]”h$]”h&]”uh1j hhõubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h Khhðubah}”(h]”h ]”h"]”h$]”h&]”uh1hîhhêubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhhåhžhhŸNh Nubhé)”}”(hŒ)the underlying device that will be cached”h]”h¸)”}”(hjch]”hŒ)the underlying device that will be cached”…””}”(hjehžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khjaubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhhåhžhhŸh¶h Nubhé)”}”(hŒthe cache device”h]”h¸)”}”(hjzh]”hŒthe cache device”…””}”(hj|hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khjxubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhhåhžhhŸh¶h Nubhé)”}”(hŒIblock size (4096 is recommended; the maximum block size is the page size)”h]”h¸)”}”(hŒIblock size (4096 is recommended; the maximum block size is the page size)”h]”hŒIblock size (4096 is recommended; the maximum block size is the page size)”…””}”(hj“hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khjubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhhåhžhhŸh¶h Nubhé)”}”(hX the number of optional parameters (the parameters with an argument count as two) start_sector n (default: 0) offset from the start of cache device in 512-byte sectors high_watermark n (default: 50) start writeback when the number of used blocks reach this watermark low_watermark x (default: 45) stop writeback when the number of used blocks drops below this watermark writeback_jobs n (default: unlimited) limit the number of blocks that are in flight during writeback. Setting this value reduces writeback throughput, but it may improve latency of read requests autocommit_blocks n (default: 64 for pmem, 65536 for ssd) when the application writes this amount of blocks without issuing the FLUSH request, the blocks are automatically committed autocommit_time ms (default: 1000) autocommit time in milliseconds. The data is automatically committed if this time passes and no FLUSH request is received fua (by default on) applicable only to persistent memory - use the FUA flag when writing data from persistent memory back to the underlying device nofua applicable only to persistent memory - don't use the FUA flag when writing back data and send the FLUSH request afterwards - some underlying devices perform better with fua, some with nofua. The user should test it cleaner when this option is activated (either in the constructor arguments or by a message), the cache will not promote new writes (however, writes to already cached blocks are promoted, to avoid data corruption due to misordered writes) and it will gradually writeback any cached data. The userspace can then monitor the cleaning process with "dmsetup status". When the number of cached blocks drops to zero, userspace can unload the dm-writecache target and replace it with dm-linear or other targets. max_age n specifies the maximum age of a block in milliseconds. If a block is stored in the cache for too long, it will be written to the underlying device and cleaned up. metadata_only only metadata is promoted to the cache. This option improves performance for heavier REQ_META workloads. pause_writeback n (default: 3000) pause writeback if there was some write I/O redirected to the origin volume in the last n milliseconds ”h]”(h¸)”}”(hŒPthe number of optional parameters (the parameters with an argument count as two)”h]”hŒPthe number of optional parameters (the parameters with an argument count as two)”…””}”(hj«hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khj§ubhŒ block_quote”“”)”}”(hXÇ start_sector n (default: 0) offset from the start of cache device in 512-byte sectors high_watermark n (default: 50) start writeback when the number of used blocks reach this watermark low_watermark x (default: 45) stop writeback when the number of used blocks drops below this watermark writeback_jobs n (default: unlimited) limit the number of blocks that are in flight during writeback. Setting this value reduces writeback throughput, but it may improve latency of read requests autocommit_blocks n (default: 64 for pmem, 65536 for ssd) when the application writes this amount of blocks without issuing the FLUSH request, the blocks are automatically committed autocommit_time ms (default: 1000) autocommit time in milliseconds. The data is automatically committed if this time passes and no FLUSH request is received fua (by default on) applicable only to persistent memory - use the FUA flag when writing data from persistent memory back to the underlying device nofua applicable only to persistent memory - don't use the FUA flag when writing back data and send the FLUSH request afterwards - some underlying devices perform better with fua, some with nofua. The user should test it cleaner when this option is activated (either in the constructor arguments or by a message), the cache will not promote new writes (however, writes to already cached blocks are promoted, to avoid data corruption due to misordered writes) and it will gradually writeback any cached data. The userspace can then monitor the cleaning process with "dmsetup status". When the number of cached blocks drops to zero, userspace can unload the dm-writecache target and replace it with dm-linear or other targets. max_age n specifies the maximum age of a block in milliseconds. If a block is stored in the cache for too long, it will be written to the underlying device and cleaned up. metadata_only only metadata is promoted to the cache. This option improves performance for heavier REQ_META workloads. pause_writeback n (default: 3000) pause writeback if there was some write I/O redirected to the origin volume in the last n milliseconds ”h]”hï)”}”(hhh]”(hô)”}”(hŒ^start_sector n (default: 0) offset from the start of cache device in 512-byte sectors”h]”(hú)”}”(hŒ$start_sector n (default: 0)”h]”hŒ$start_sector n (default: 0)”…””}”(hjÆhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h KhjÂubj )”}”(hhh]”h¸)”}”(hŒ9offset from the start of cache device in 512-byte sectors”h]”hŒ9offset from the start of cache device in 512-byte sectors”…””}”(hj×hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KhjÔubah}”(h]”h ]”h"]”h$]”h&]”uh1j hjÂubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h Khj¿ubhô)”}”(hŒihigh_watermark n (default: 50) start writeback when the number of used blocks reach this watermark”h]”(hú)”}”(hŒ%high_watermark n (default: 50)”h]”hŒ%high_watermark n (default: 50)”…””}”(hjõhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h Khjñubj )”}”(hhh]”h¸)”}”(hŒCstart writeback when the number of used blocks reach this watermark”h]”hŒCstart writeback when the number of used blocks reach this watermark”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khjubah}”(h]”h ]”h"]”h$]”h&]”uh1j hjñubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h Khj¿ubhô)”}”(hŒnlow_watermark x (default: 45) stop writeback when the number of used blocks drops below this watermark”h]”(hú)”}”(hŒ%low_watermark x (default: 45)”h]”hŒ%low_watermark x (default: 45)”…””}”(hj$hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h Khj ubj )”}”(hhh]”h¸)”}”(hŒHstop writeback when the number of used blocks drops below this watermark”h]”hŒHstop writeback when the number of used blocks drops below this watermark”…””}”(hj5hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khj2ubah}”(h]”h ]”h"]”h$]”h&]”uh1j hj ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h Khj¿ubhô)”}”(hŒÉwriteback_jobs n (default: unlimited) limit the number of blocks that are in flight during writeback. Setting this value reduces writeback throughput, but it may improve latency of read requests”h]”(hú)”}”(hŒ,writeback_jobs n (default: unlimited)”h]”hŒ,writeback_jobs n (default: unlimited)”…””}”(hjShžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h K"hjOubj )”}”(hhh]”h¸)”}”(hŒœlimit the number of blocks that are in flight during writeback. Setting this value reduces writeback throughput, but it may improve latency of read requests”h]”hŒœlimit the number of blocks that are in flight during writeback. Setting this value reduces writeback throughput, but it may improve latency of read requests”…””}”(hjdhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K!hjaubah}”(h]”h ]”h"]”h$]”h&]”uh1j hjOubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h K"hj¿ubhô)”}”(hŒ¹autocommit_blocks n (default: 64 for pmem, 65536 for ssd) when the application writes this amount of blocks without issuing the FLUSH request, the blocks are automatically committed”h]”(hú)”}”(hŒ=autocommit_blocks n (default: 64 for pmem, 65536 for ssd)”h]”hŒ=autocommit_blocks n (default: 64 for pmem, 65536 for ssd)”…””}”(hj‚hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h K&hj~ubj )”}”(hhh]”h¸)”}”(hŒ{when the application writes this amount of blocks without issuing the FLUSH request, the blocks are automatically committed”h]”hŒ{when the application writes this amount of blocks without issuing the FLUSH request, the blocks are automatically committed”…””}”(hj“hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K%hjubah}”(h]”h ]”h"]”h$]”h&]”uh1j hj~ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h K&hj¿ubhô)”}”(hŒ¡autocommit_time ms (default: 1000) autocommit time in milliseconds. The data is automatically committed if this time passes and no FLUSH request is received”h]”(hú)”}”(hŒ'autocommit_time ms (default: 1000)”h]”hŒ'autocommit_time ms (default: 1000)”…””}”(hj±hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h K*hj­ubj )”}”(hhh]”h¸)”}”(hŒyautocommit time in milliseconds. The data is automatically committed if this time passes and no FLUSH request is received”h]”hŒyautocommit time in milliseconds. The data is automatically committed if this time passes and no FLUSH request is received”…””}”(hjÂhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K)hj¿ubah}”(h]”h ]”h"]”h$]”h&]”uh1j hj­ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h K*hj¿ubhô)”}”(hŒ¦fua (by default on) applicable only to persistent memory - use the FUA flag when writing data from persistent memory back to the underlying device”h]”(hú)”}”(hŒ'fua (by default on)”h]”hŒ'fua (by default on)”…””}”(hjàhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h K.hjÜubj )”}”(hhh]”h¸)”}”(hŒ~applicable only to persistent memory - use the FUA flag when writing data from persistent memory back to the underlying device”h]”hŒ~applicable only to persistent memory - use the FUA flag when writing data from persistent memory back to the underlying device”…””}”(hjñhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K-hjîubah}”(h]”h ]”h"]”h$]”h&]”uh1j hjÜubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h K.hj¿ubhô)”}”(hŒßnofua applicable only to persistent memory - don't use the FUA flag when writing back data and send the FLUSH request afterwards - some underlying devices perform better with fua, some with nofua. The user should test it”h]”(hú)”}”(hŒnofua”h]”hŒnofua”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h K5hj ubj )”}”(hhh]”(h¸)”}”(hŒzapplicable only to persistent memory - don't use the FUA flag when writing back data and send the FLUSH request afterwards”h]”hŒ|applicable only to persistent memory - don’t use the FUA flag when writing back data and send the FLUSH request afterwards”…””}”(hj hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K1hjubj)”}”(hhh]”hé)”}”(hŒYsome underlying devices perform better with fua, some with nofua. The user should test it”h]”h¸)”}”(hŒYsome underlying devices perform better with fua, some with nofua. The user should test it”h]”hŒYsome underlying devices perform better with fua, some with nofua. The user should test it”…””}”(hj5hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K5hj1ubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhj.ubah}”(h]”h ]”h"]”h$]”h&]”jGjHuh1jhŸh¶h K5hjubeh}”(h]”h ]”h"]”h$]”h&]”uh1j hj ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h K5hj¿ubhô)”}”(hX÷cleaner when this option is activated (either in the constructor arguments or by a message), the cache will not promote new writes (however, writes to already cached blocks are promoted, to avoid data corruption due to misordered writes) and it will gradually writeback any cached data. The userspace can then monitor the cleaning process with "dmsetup status". When the number of cached blocks drops to zero, userspace can unload the dm-writecache target and replace it with dm-linear or other targets.”h]”(hú)”}”(hŒcleaner”h]”hŒcleaner”…””}”(hj_hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h K@hj[ubj )”}”(hhh]”h¸)”}”(hXïwhen this option is activated (either in the constructor arguments or by a message), the cache will not promote new writes (however, writes to already cached blocks are promoted, to avoid data corruption due to misordered writes) and it will gradually writeback any cached data. The userspace can then monitor the cleaning process with "dmsetup status". When the number of cached blocks drops to zero, userspace can unload the dm-writecache target and replace it with dm-linear or other targets.”h]”hXówhen this option is activated (either in the constructor arguments or by a message), the cache will not promote new writes (however, writes to already cached blocks are promoted, to avoid data corruption due to misordered writes) and it will gradually writeback any cached data. The userspace can then monitor the cleaning process with “dmsetup statusâ€. When the number of cached blocks drops to zero, userspace can unload the dm-writecache target and replace it with dm-linear or other targets.”…””}”(hjphžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K8hjmubah}”(h]”h ]”h"]”h$]”h&]”uh1j hj[ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h K@hj¿ubhô)”}”(hŒ«max_age n specifies the maximum age of a block in milliseconds. If a block is stored in the cache for too long, it will be written to the underlying device and cleaned up.”h]”(hú)”}”(hŒ max_age n”h]”hŒ max_age n”…””}”(hjŽhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h KDhjŠubj )”}”(hhh]”h¸)”}”(hŒ¡specifies the maximum age of a block in milliseconds. If a block is stored in the cache for too long, it will be written to the underlying device and cleaned up.”h]”hŒ¡specifies the maximum age of a block in milliseconds. If a block is stored in the cache for too long, it will be written to the underlying device and cleaned up.”…””}”(hjŸhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KChjœubah}”(h]”h ]”h"]”h$]”h&]”uh1j hjŠubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h KDhj¿ubhô)”}”(hŒvmetadata_only only metadata is promoted to the cache. This option improves performance for heavier REQ_META workloads.”h]”(hú)”}”(hŒ metadata_only”h]”hŒ metadata_only”…””}”(hj½hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h KGhj¹ubj )”}”(hhh]”h¸)”}”(hŒhonly metadata is promoted to the cache. This option improves performance for heavier REQ_META workloads.”h]”hŒhonly metadata is promoted to the cache. This option improves performance for heavier REQ_META workloads.”…””}”(hjÎhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KGhjËubah}”(h]”h ]”h"]”h$]”h&]”uh1j hj¹ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h KGhj¿ubhô)”}”(hŒpause_writeback n (default: 3000) pause writeback if there was some write I/O redirected to the origin volume in the last n milliseconds ”h]”(hú)”}”(hŒ'pause_writeback n (default: 3000)”h]”hŒ'pause_writeback n (default: 3000)”…””}”(hjìhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h KKhjèubj )”}”(hhh]”h¸)”}”(hŒfpause writeback if there was some write I/O redirected to the origin volume in the last n milliseconds”h]”hŒfpause writeback if there was some write I/O redirected to the origin volume in the last n milliseconds”…””}”(hjýhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KJhjúubah}”(h]”h ]”h"]”h$]”h&]”uh1j hjèubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h KKhj¿ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hîhj»ubah}”(h]”h ]”h"]”h$]”h&]”uh1j¹hŸh¶h Khj§ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hèhhåhžhhŸh¶h Nubeh}”(h]”h ]”h"]”h$]”h&]”Œenumtype”Œarabic”Œprefix”hŒsuffix”Œ.”uh1hãhh£hžhhŸh¶h Kubh¸)”}”(hŒStatus:”h]”hŒStatus:”…””}”(hj4hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KMhh£hžhubhä)”}”(hhh]”(hé)”}”(hŒAerror indicator - 0 if there was no error, otherwise error number”h]”h¸)”}”(hjGh]”hŒAerror indicator - 0 if there was no error, otherwise error number”…””}”(hjIhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KOhjEubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjBhžhhŸh¶h Nubhé)”}”(hŒthe number of blocks”h]”h¸)”}”(hj^h]”hŒthe number of blocks”…””}”(hj`hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KPhj\ubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjBhžhhŸh¶h Nubhé)”}”(hŒthe number of free blocks”h]”h¸)”}”(hjuh]”hŒthe number of free blocks”…””}”(hjwhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KQhjsubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjBhžhhŸh¶h Nubhé)”}”(hŒ$the number of blocks under writeback”h]”h¸)”}”(hjŒh]”hŒ$the number of blocks under writeback”…””}”(hjŽhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KRhjŠubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjBhžhhŸh¶h Nubhé)”}”(hŒthe number of read blocks”h]”h¸)”}”(hj£h]”hŒthe number of read blocks”…””}”(hj¥hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KShj¡ubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjBhžhhŸh¶h Nubhé)”}”(hŒ,the number of read blocks that hit the cache”h]”h¸)”}”(hjºh]”hŒ,the number of read blocks that hit the cache”…””}”(hj¼hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KThj¸ubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjBhžhhŸh¶h Nubhé)”}”(hŒthe number of write blocks”h]”h¸)”}”(hjÑh]”hŒthe number of write blocks”…””}”(hjÓhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KUhjÏubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjBhžhhŸh¶h Nubhé)”}”(hŒ5the number of write blocks that hit uncommitted block”h]”h¸)”}”(hjèh]”hŒ5the number of write blocks that hit uncommitted block”…””}”(hjêhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KVhjæubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjBhžhhŸh¶h Nubhé)”}”(hŒ3the number of write blocks that hit committed block”h]”h¸)”}”(hjÿh]”hŒ3the number of write blocks that hit committed block”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KWhjýubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjBhžhhŸh¶h Nubhé)”}”(hŒ0the number of write blocks that bypass the cache”h]”h¸)”}”(hjh]”hŒ0the number of write blocks that bypass the cache”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KXhjubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjBhžhhŸh¶h Nubhé)”}”(hŒ:the number of write blocks that are allocated in the cache”h]”h¸)”}”(hj-h]”hŒ:the number of write blocks that are allocated in the cache”…””}”(hj/hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KYhj+ubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjBhžhhŸh¶h Nubhé)”}”(hŒ=the number of write requests that are blocked on the freelist”h]”h¸)”}”(hjDh]”hŒ=the number of write requests that are blocked on the freelist”…””}”(hjFhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KZhjBubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjBhžhhŸh¶h Nubhé)”}”(hŒthe number of flush requests”h]”h¸)”}”(hj[h]”hŒthe number of flush requests”…””}”(hj]hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K[hjYubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjBhžhhŸh¶h Nubhé)”}”(hŒthe number of discarded blocks ”h]”h¸)”}”(hŒthe number of discarded blocks”h]”hŒthe number of discarded blocks”…””}”(hjthžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K\hjpubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjBhžhhŸh¶h Nubeh}”(h]”h ]”h"]”h$]”h&]”j/j0j1hj2j3uh1hãhh£hžhhŸh¶h KOubhï)”}”(hhh]”hô)”}”(hX_Messages: flush Flush the cache device. The message returns successfully if the cache device was flushed without an error flush_on_suspend Flush the cache device on next suspend. Use this message when you are going to remove the cache device. The proper sequence for removing the cache device is: 1. send the "flush_on_suspend" message 2. load an inactive table with a linear target that maps to the underlying device 3. suspend the device 4. ask for status and verify that there are no errors 5. resume the device, so that it will use the linear target 6. the cache device is now inactive and it can be deleted cleaner See above "cleaner" constructor documentation. clear_stats Clear the statistics that are reported on the status line”h]”(hú)”}”(hŒ Messages:”h]”hŒ Messages:”…””}”(hj•hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h Kqhj‘ubj )”}”(hhh]”hï)”}”(hhh]”(hô)”}”(hŒoflush Flush the cache device. The message returns successfully if the cache device was flushed without an error”h]”(hú)”}”(hŒflush”h]”hŒflush”…””}”(hj­hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h K`hj©ubj )”}”(hhh]”h¸)”}”(hŒiFlush the cache device. The message returns successfully if the cache device was flushed without an error”h]”hŒiFlush the cache device. The message returns successfully if the cache device was flushed without an error”…””}”(hj¾hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K`hj»ubah}”(h]”h ]”h"]”h$]”h&]”uh1j hj©ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h K`hj¦ubhô)”}”(hXðflush_on_suspend Flush the cache device on next suspend. Use this message when you are going to remove the cache device. The proper sequence for removing the cache device is: 1. send the "flush_on_suspend" message 2. load an inactive table with a linear target that maps to the underlying device 3. suspend the device 4. ask for status and verify that there are no errors 5. resume the device, so that it will use the linear target 6. the cache device is now inactive and it can be deleted”h]”(hú)”}”(hŒflush_on_suspend”h]”hŒflush_on_suspend”…””}”(hjÜhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h KmhjØubj )”}”(hhh]”(h¸)”}”(hŒFlush the cache device on next suspend. Use this message when you are going to remove the cache device. The proper sequence for removing the cache device is:”h]”hŒFlush the cache device on next suspend. Use this message when you are going to remove the cache device. The proper sequence for removing the cache device is:”…””}”(hjíhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Kchjêubhä)”}”(hhh]”(hé)”}”(hŒ#send the "flush_on_suspend" message”h]”h¸)”}”(hjh]”hŒ'send the “flush_on_suspend†message”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Kghjþubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjûubhé)”}”(hŒNload an inactive table with a linear target that maps to the underlying device”h]”h¸)”}”(hŒNload an inactive table with a linear target that maps to the underlying device”h]”hŒNload an inactive table with a linear target that maps to the underlying device”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khhjubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjûubhé)”}”(hŒsuspend the device”h]”h¸)”}”(hj/h]”hŒsuspend the device”…””}”(hj1hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Kjhj-ubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjûubhé)”}”(hŒ2ask for status and verify that there are no errors”h]”h¸)”}”(hjFh]”hŒ2ask for status and verify that there are no errors”…””}”(hjHhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KkhjDubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjûubhé)”}”(hŒ8resume the device, so that it will use the linear target”h]”h¸)”}”(hŒ8resume the device, so that it will use the linear target”h]”hŒ8resume the device, so that it will use the linear target”…””}”(hj_hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Klhj[ubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjûubhé)”}”(hŒ6the cache device is now inactive and it can be deleted”h]”h¸)”}”(hjuh]”hŒ6the cache device is now inactive and it can be deleted”…””}”(hjwhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Knhjsubah}”(h]”h ]”h"]”h$]”h&]”uh1hèhjûubeh}”(h]”h ]”h"]”h$]”h&]”j/j0j1hj2j3uh1hãhjêubeh}”(h]”h ]”h"]”h$]”h&]”uh1j hjØubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h Kmhj¦ubhô)”}”(hŒ6cleaner See above "cleaner" constructor documentation.”h]”(hú)”}”(hŒcleaner”h]”hŒcleaner”…””}”(hj hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h Kohjœubj )”}”(hhh]”h¸)”}”(hŒ.See above "cleaner" constructor documentation.”h]”hŒ2See above “cleaner†constructor documentation.”…””}”(hj±hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Kphj®ubah}”(h]”h ]”h"]”h$]”h&]”uh1j hjœubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h Kohj¦ubhô)”}”(hŒEclear_stats Clear the statistics that are reported on the status line”h]”(hú)”}”(hŒ clear_stats”h]”hŒ clear_stats”…””}”(hjÏhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hùhŸh¶h KqhjËubj )”}”(hhh]”h¸)”}”(hŒ9Clear the statistics that are reported on the status line”h]”hŒ9Clear the statistics that are reported on the status line”…””}”(hjàhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KrhjÝubah}”(h]”h ]”h"]”h$]”h&]”uh1j hjËubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h Kqhj¦ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hîhj£ubah}”(h]”h ]”h"]”h$]”h&]”uh1j hj‘ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hóhŸh¶h KqhjŽubah}”(h]”h ]”h"]”h$]”h&]”uh1hîhh£hžhhŸNh Nubeh}”(h]”Œwritecache-target”ah ]”h"]”Œwritecache target”ah$]”h&]”uh1h¡hhhžhhŸh¶h Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”h¶uh1hŒcurrent_source”NŒ current_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(h¦NŒ generator”NŒ datestamp”NŒ source_link”NŒ source_url”NŒ toc_backlinks”Œentry”Œfootnote_backlinks”KŒ sectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒ strip_classes”NŒ report_level”KŒ halt_level”KŒexit_status_level”KŒdebug”NŒwarning_stream”NŒ traceback”ˆŒinput_encoding”Œ utf-8-sig”Œinput_encoding_error_handler”Œstrict”Œoutput_encoding”Œutf-8”Œoutput_encoding_error_handler”j=Œerror_encoding”Œutf-8”Œerror_encoding_error_handler”Œbackslashreplace”Œ language_code”Œen”Œrecord_dependencies”NŒconfig”NŒ id_prefix”hŒauto_id_prefix”Œid”Œ dump_settings”NŒdump_internals”NŒdump_transforms”NŒdump_pseudo_xml”NŒexpose_internals”NŒstrict_visitor”NŒ_disable_config”NŒ_source”h¶Œ _destination”NŒ _config_files”]”Œ7/var/lib/git/docbuild/linux/Documentation/docutils.conf”aŒfile_insertion_enabled”ˆŒ raw_enabled”KŒline_length_limit”M'Œpep_references”NŒ pep_base_url”Œhttps://peps.python.org/”Œpep_file_url_template”Œpep-%04d”Œrfc_references”NŒ rfc_base_url”Œ&https://datatracker.ietf.org/doc/html/”Œ tab_width”KŒtrim_footnote_reference_space”‰Œsyntax_highlight”Œlong”Œ smart_quotes”ˆŒsmartquotes_locales”]”Œcharacter_level_inline_markup”‰Œdoctitle_xform”‰Œ docinfo_xform”KŒsectsubtitle_xform”‰Œ image_loading”Œlink”Œembed_stylesheet”‰Œcloak_email_addresses”ˆŒsection_self_link”‰Œenv”NubŒreporter”NŒindirect_targets”]”Œsubstitution_defs”}”Œsubstitution_names”}”Œrefnames”}”Œrefids”}”Œnameids”}”jjsŒ nametypes”}”j‰sh}”jh£sŒ footnote_refs”}”Œ citation_refs”}”Œ autofootnotes”]”Œautofootnote_refs”]”Œsymbol_footnotes”]”Œsymbol_footnote_refs”]”Œ footnotes”]”Œ citations”]”Œautofootnote_start”KŒsymbol_footnote_start”KŒ id_counter”Œ collections”ŒCounter”“”}”…”R”Œparse_messages”]”Œtransform_messages”]”Œ transformer”NŒ include_log”]”Œ decoration”Nhžhub.