| Measurement |
Description |
Measurement Unit |
Interpretation |
| State |
Indicates the current state of this LUN. |
|
If the state reported by this measure is Bound, it indicates that the LUN is currently in a bound state. A bind creates LUNs on a RAID GROUP. Binding a LUN involves the preparation of allocated storage space. This preparation is particularly
important when storage capacity is being reallocated for reuse.
LUNs are bound after RAID GROUPS are created. LUNs are available for use immediately after they are created, but the bind is not strictly complete until after all the bound storage has been prepared and verified.
During the preparation step, the storage allocated to the LUN is overwritten with binary zeroes. These zeroes erase any previous data from the storage and set up for the parity calculation. When zeroing is complete, parity and metadata is calculated for the LUN sectors.
If the state reported by this measure is Not bound, it indicates that the LUN is currently in an unbound state.
The numeric values that correspond to each of the states discussed above are as follows:
| Numeric Value |
State |
| 1 |
Bound |
| 0 |
Not bound |
Note:By default, this measure reports the values Bound or Not bound to indicate the state of a LUN. The graph of this measure however, represents the cache status using the numeric equivalents - 0 or 1.
Use the detailed diagnosis of this measure to view additional details of a LUN. |
| Hard_errors |
Indicates the number of hard errors on this LUN. |
Number |
The values and their respective states are listed below:
- 10 - critical
- 5 - major
- 2 - minor
Increase in the value of this measure indicates that the LUN life is going to end or fail. |
| Soft_errors |
Indicates the total number of uncorrected read and write errors on this LUN. |
Number |
The values and their respective states are listed below:
- 10 - critical
- 15 - major
- 2 - minor
Increase in value of this measure indicates disk life is going to end or fail. |
| Queue_length |
Indicates the average number of requests to this LUN that are in queue. |
Number |
A very high value could indicate a processing bottleneck on this LUN. |
| Read_cache_hits |
Indicates the number of times read requests to this LUN were fulfilled by the read cache. |
Number |
A high value is desired for this measure. |
| Write_cache_hits |
Indicates the number of times write requests to this LUN were fulfilled by the write cache. |
Number |
A high value is desired for this measure. |
| Read_cache_misses |
Indicates the number of times read requests to this LUN were not serviced by the read cache. |
Number |
Ideally, the value of this measure should be low. |
| Read_hit_ratio |
Indicates the percentage of read requests to this LUN that were serviced by the cache. |
Percent |
Ideally, the value of this measure should be high. A low value indicates that many read requests are serviced by direct disk accesses, which is a more expensive operation in terms of processing overheads. |
| Write_hit_ratio |
Indicates the percentage of write requests to this LUN that were serviced by the cache. |
Percent |
Ideally, the value of this measure should be high. A low value indicates that data is often directly written to the disk, which is a more expensive operation in terms of processing overheads. |
| Read_requests |
Indicates the number of read requests made per second to this LUN. |
Reqs/Sec |
Comparing the value of these measures across LUNs will clearly indicate which LUN is the busiest in terms of the number of read and write requests handled - it could also shed light on irregularities in load balancing across the LUNs. |
| Write_requests |
Indicates the number of write requests made per second to this LUN. |
Reqs/Sec |
| Data_reads |
Indicates the rate at which data was read from this LUN. |
Blocks/Sec |
Comparing the value of these measures across LUNs will clearly indicate which LUN is the busiest in terms of the rate at which data is read and written - it could also shed light on irregularities in load balancing across the LUNs. |
| Data_writes |
Indicates the rate at which data was written to this LUN. |
Blocks/Sec |
| Total_io |
Indicates the rate of the I/O activity on this LUN. |
Number |
|
| Rebuilt |
Indicates the percentage of this LUN that has been rebuilt. |
Percent |
A rebuild replaces a failed hard disk within a RAID group with an operational disk. If one or more LUNs are bound to the RAID group with the failed disk, then, all the LUNs affected by the failure are rebuilt. A rebuild restores a LUN to its fully assigned number of hard drives using an available hot spare should a drive in one of the RAID groups fail. LUNs are rebuilt one by one. Each LUN is rebuilt by its owning Storage Processor (SP). |
| Bound |
Indicates the percentage of the LUN binding process that is complete. |
Percent |
A bind is an information organization, data security, and data integrity feature of CLARiiON. Binding a LUN involves the preparation of allocated storage space. This preparation is particularly important when storage capacity is being reallocated for reuse. This reuse of storage includes erasing any previous data found on the hard drives, and the setting of parity and metadata for the storage.
LUNs are typically available for use immediately after they are bound. However, the bind is not strictly complete until after all the bound storage has been prepared and verified. Depending on the LUN size and verify priority, these two steps may take several hours. Using the value of this measure, you will be able to track the progress of the binding function, and will be able to gauge how much longer it will take for the binding to complete. |
| Lun_capacity_mb |
Indicates the total capacity of this LUN. |
GB |
|
| Lun_capacity_blocks |
Indicates the LUN size in blocks. |
Blocks |
|