| What: /sys/block/<disk>/stat |
| Date: February 2008 |
| Contact: Jerome Marchand <jmarchan@redhat.com> |
| Description: |
| The /sys/block/<disk>/stat files displays the I/O |
| statistics of disk <disk>. They contain 11 fields: |
| 1 - reads completed succesfully |
| 2 - reads merged |
| 3 - sectors read |
| 4 - time spent reading (ms) |
| 5 - writes completed |
| 6 - writes merged |
| 7 - sectors written |
| 8 - time spent writing (ms) |
| 9 - I/Os currently in progress |
| 10 - time spent doing I/Os (ms) |
| 11 - weighted time spent doing I/Os (ms) |
| For more details refer Documentation/iostats.txt |
| |
| |
| What: /sys/block/<disk>/<part>/stat |
| Date: February 2008 |
| Contact: Jerome Marchand <jmarchan@redhat.com> |
| Description: |
| The /sys/block/<disk>/<part>/stat files display the |
| I/O statistics of partition <part>. The format is the |
| same as the above-written /sys/block/<disk>/stat |
| format. |
| |
| |
| What: /sys/block/<disk>/integrity/format |
| Date: June 2008 |
| Contact: Martin K. Petersen <martin.petersen@oracle.com> |
| Description: |
| Metadata format for integrity capable block device. |
| E.g. T10-DIF-TYPE1-CRC. |
| |
| |
| What: /sys/block/<disk>/integrity/read_verify |
| Date: June 2008 |
| Contact: Martin K. Petersen <martin.petersen@oracle.com> |
| Description: |
| Indicates whether the block layer should verify the |
| integrity of read requests serviced by devices that |
| support sending integrity metadata. |
| |
| |
| What: /sys/block/<disk>/integrity/tag_size |
| Date: June 2008 |
| Contact: Martin K. Petersen <martin.petersen@oracle.com> |
| Description: |
| Number of bytes of integrity tag space available per |
| 512 bytes of data. |
| |
| |
| What: /sys/block/<disk>/integrity/write_generate |
| Date: June 2008 |
| Contact: Martin K. Petersen <martin.petersen@oracle.com> |
| Description: |
| Indicates whether the block layer should automatically |
| generate checksums for write requests bound for |
| devices that support receiving integrity metadata. |
| |
| What: /sys/block/<disk>/alignment_offset |
| Date: April 2009 |
| Contact: Martin K. Petersen <martin.petersen@oracle.com> |
| Description: |
| Storage devices may report a physical block size that is |
| bigger than the logical block size (for instance a drive |
| with 4KB physical sectors exposing 512-byte logical |
| blocks to the operating system). This parameter |
| indicates how many bytes the beginning of the device is |
| offset from the disk's natural alignment. |
| |
| What: /sys/block/<disk>/<partition>/alignment_offset |
| Date: April 2009 |
| Contact: Martin K. Petersen <martin.petersen@oracle.com> |
| Description: |
| Storage devices may report a physical block size that is |
| bigger than the logical block size (for instance a drive |
| with 4KB physical sectors exposing 512-byte logical |
| blocks to the operating system). This parameter |
| indicates how many bytes the beginning of the partition |
| is offset from the disk's natural alignment. |
| |
| What: /sys/block/<disk>/queue/logical_block_size |
| Date: May 2009 |
| Contact: Martin K. Petersen <martin.petersen@oracle.com> |
| Description: |
| This is the smallest unit the storage device can |
| address. It is typically 512 bytes. |
| |
| What: /sys/block/<disk>/queue/physical_block_size |
| Date: May 2009 |
| Contact: Martin K. Petersen <martin.petersen@oracle.com> |
| Description: |
| This is the smallest unit the storage device can write |
| without resorting to read-modify-write operation. It is |
| usually the same as the logical block size but may be |
| bigger. One example is SATA drives with 4KB sectors |
| that expose a 512-byte logical block size to the |
| operating system. |
| |
| What: /sys/block/<disk>/queue/minimum_io_size |
| Date: April 2009 |
| Contact: Martin K. Petersen <martin.petersen@oracle.com> |
| Description: |
| Storage devices may report a preferred minimum I/O size, |
| which is the smallest request the device can perform |
| without incurring a read-modify-write penalty. For disk |
| drives this is often the physical block size. For RAID |
| arrays it is often the stripe chunk size. |
| |
| What: /sys/block/<disk>/queue/optimal_io_size |
| Date: April 2009 |
| Contact: Martin K. Petersen <martin.petersen@oracle.com> |
| Description: |
| Storage devices may report an optimal I/O size, which is |
| the device's preferred unit of receiving I/O. This is |
| rarely reported for disk drives. For RAID devices it is |
| usually the stripe width or the internal block size. |