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Commit | Line | Data |
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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: | |
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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. |