1 What: /sys/block/<disk>/stat
3 Contact: Jerome Marchand <jmarchan@redhat.com>
5 The /sys/block/<disk>/stat files displays the I/O
6 statistics of disk <disk>. They contain 11 fields:
7 1 - reads completed successfully
10 4 - time spent reading (ms)
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
21 What: /sys/block/<disk>/<part>/stat
23 Contact: Jerome Marchand <jmarchan@redhat.com>
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
31 What: /sys/block/<disk>/integrity/format
33 Contact: Martin K. Petersen <martin.petersen@oracle.com>
35 Metadata format for integrity capable block device.
36 E.g. T10-DIF-TYPE1-CRC.
39 What: /sys/block/<disk>/integrity/read_verify
41 Contact: Martin K. Petersen <martin.petersen@oracle.com>
43 Indicates whether the block layer should verify the
44 integrity of read requests serviced by devices that
45 support sending integrity metadata.
48 What: /sys/block/<disk>/integrity/tag_size
50 Contact: Martin K. Petersen <martin.petersen@oracle.com>
52 Number of bytes of integrity tag space available per
56 What: /sys/block/<disk>/integrity/write_generate
58 Contact: Martin K. Petersen <martin.petersen@oracle.com>
60 Indicates whether the block layer should automatically
61 generate checksums for write requests bound for
62 devices that support receiving integrity metadata.
64 What: /sys/block/<disk>/alignment_offset
66 Contact: Martin K. Petersen <martin.petersen@oracle.com>
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.
75 What: /sys/block/<disk>/<partition>/alignment_offset
77 Contact: Martin K. Petersen <martin.petersen@oracle.com>
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.
86 What: /sys/block/<disk>/queue/logical_block_size
88 Contact: Martin K. Petersen <martin.petersen@oracle.com>
90 This is the smallest unit the storage device can
91 address. It is typically 512 bytes.
93 What: /sys/block/<disk>/queue/physical_block_size
95 Contact: Martin K. Petersen <martin.petersen@oracle.com>
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.
105 What: /sys/block/<disk>/queue/minimum_io_size
107 Contact: Martin K. Petersen <martin.petersen@oracle.com>
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
119 What: /sys/block/<disk>/queue/optimal_io_size
121 Contact: Martin K. Petersen <martin.petersen@oracle.com>
123 Storage devices may report an optimal I/O size, which is
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.