projects / mirror_ubuntu-zesty-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 0e53c2be JM |
1 | What: /sys/block/<disk>/stat |
| 2 | Date: February 2008 | |
| 3 | Contact: Jerome Marchand <jmarchan@redhat.com> | |
| 4 | Description: | |
| 5 | The /sys/block/<disk>/stat files displays the I/O | |
| 6 | statistics of disk <disk>. They contain 11 fields: | |
| af901ca1 | 7 | 1 - reads completed successfully |
| 0e53c2be JM |
8 | 2 - reads merged |
| 9 | 3 - sectors read | |
| 10 | 4 - time spent reading (ms) | |
| 11 | 5 - writes completed | |
| 12 | 6 - writes merged | |
| 13 | 7 - sectors written | |
| 14 | 8 - time spent writing (ms) | |
| 15 | 9 - I/Os currently in progress | |
| 16 | 10 - time spent doing I/Os (ms) | |
| 17 | 11 - weighted time spent doing I/Os (ms) | |
| 18 | For more details refer Documentation/iostats.txt | |
| 19 | ||
| 20 | ||
| 21 | What: /sys/block/<disk>/<part>/stat | |
| 22 | Date: February 2008 | |
| 23 | Contact: Jerome Marchand <jmarchan@redhat.com> | |
| 24 | Description: | |
| 25 | The /sys/block/<disk>/<part>/stat files display the | |
| 26 | I/O statistics of partition <part>. The format is the | |
| 27 | same as the above-written /sys/block/<disk>/stat | |
| 28 | format. | |
| c1c72b59 MP |
29 | |
| 30 | ||
| 31 | What: /sys/block/<disk>/integrity/format | |
| 32 | Date: June 2008 | |
| 33 | Contact: Martin K. Petersen <martin.petersen@oracle.com> | |
| 34 | Description: | |
| 35 | Metadata format for integrity capable block device. | |
| 36 | E.g. T10-DIF-TYPE1-CRC. | |
| 37 | ||
| 38 | ||
| 39 | What: /sys/block/<disk>/integrity/read_verify | |
| 40 | Date: June 2008 | |
| 41 | Contact: Martin K. Petersen <martin.petersen@oracle.com> | |
| 42 | Description: | |
| 43 | Indicates whether the block layer should verify the | |
| 44 | integrity of read requests serviced by devices that | |
| 45 | support sending integrity metadata. | |
| 46 | ||
| 47 | ||
| 48 | What: /sys/block/<disk>/integrity/tag_size | |
| 49 | Date: June 2008 | |
| 50 | Contact: Martin K. Petersen <martin.petersen@oracle.com> | |
| 51 | Description: | |
| 52 | Number of bytes of integrity tag space available per | |
| 53 | 512 bytes of data. | |
| 54 | ||
| 55 | ||
| 56 | What: /sys/block/<disk>/integrity/write_generate | |
| 57 | Date: June 2008 | |
| 58 | Contact: Martin K. Petersen <martin.petersen@oracle.com> | |
| 59 | Description: | |
| 60 | Indicates whether the block layer should automatically | |
| 61 | generate checksums for write requests bound for | |
| 62 | devices that support receiving integrity metadata. | |
| c72758f3 MP |
63 | |
| 64 | What: /sys/block/<disk>/alignment_offset | |
| 65 | Date: April 2009 | |
| 66 | Contact: Martin K. Petersen <martin.petersen@oracle.com> | |
| 67 | Description: | |
| 68 | Storage devices may report a physical block size that is | |
| 69 | bigger than the logical block size (for instance a drive | |
| 70 | with 4KB physical sectors exposing 512-byte logical | |
| 71 | blocks to the operating system). This parameter | |
| 72 | indicates how many bytes the beginning of the device is | |
| 73 | offset from the disk's natural alignment. | |
| 74 | ||
| 75 | What: /sys/block/<disk>/<partition>/alignment_offset | |
| 76 | Date: April 2009 | |
| 77 | Contact: Martin K. Petersen <martin.petersen@oracle.com> | |
| 78 | Description: | |
| 79 | Storage devices may report a physical block size that is | |
| 80 | bigger than the logical block size (for instance a drive | |
| 81 | with 4KB physical sectors exposing 512-byte logical | |
| 82 | blocks to the operating system). This parameter | |
| 83 | indicates how many bytes the beginning of the partition | |
| 84 | is offset from the disk's natural alignment. | |
| 85 | ||
| 86 | What: /sys/block/<disk>/queue/logical_block_size | |
| 87 | Date: May 2009 | |
| 88 | Contact: Martin K. Petersen <martin.petersen@oracle.com> | |
| 89 | Description: | |
| 90 | This is the smallest unit the storage device can | |
| 91 | address. It is typically 512 bytes. | |
| 92 | ||
| 93 | What: /sys/block/<disk>/queue/physical_block_size | |
| 94 | Date: May 2009 | |
| 95 | Contact: Martin K. Petersen <martin.petersen@oracle.com> | |
| 96 | Description: | |
| 7e5f5fb0 MP |
97 | This is the smallest unit a physical storage device can |
| 98 | write atomically. It is usually the same as the logical | |
| 99 | block size but may be bigger. One example is SATA | |
| 100 | drives with 4KB sectors that expose a 512-byte logical | |
| 101 | block size to the operating system. For stacked block | |
| 102 | devices the physical_block_size variable contains the | |
| 103 | maximum physical_block_size of the component devices. | |
| c72758f3 MP |
104 | |
| 105 | What: /sys/block/<disk>/queue/minimum_io_size | |
| 106 | Date: April 2009 | |
| 107 | Contact: Martin K. Petersen <martin.petersen@oracle.com> | |
| 108 | Description: | |
| 7e5f5fb0 MP |
109 | Storage devices may report a granularity or preferred |
| 110 | minimum I/O size which is the smallest request the | |
| 111 | device can perform without incurring a performance | |
| 112 | penalty. For disk drives this is often the physical | |
| 113 | block size. For RAID arrays it is often the stripe | |
| 114 | chunk size. A properly aligned multiple of | |
| 115 | minimum_io_size is the preferred request size for | |
| 116 | workloads where a high number of I/O operations is | |
| 117 | desired. | |
| c72758f3 MP |
118 | |
| 119 | What: /sys/block/<disk>/queue/optimal_io_size | |
| 120 | Date: April 2009 | |
| 121 | Contact: Martin K. Petersen <martin.petersen@oracle.com> | |
| 122 | Description: | |
| 123 | Storage devices may report an optimal I/O size, which is | |
| 7e5f5fb0 MP |
124 | the device's preferred unit for sustained I/O. This is |
| 125 | rarely reported for disk drives. For RAID arrays it is | |
| 126 | usually the stripe width or the internal track size. A | |
| 127 | properly aligned multiple of optimal_io_size is the | |
| 128 | preferred request size for workloads where sustained | |
| 129 | throughput is desired. If no optimal I/O size is | |
| 130 | reported this file contains 0. |