RAID arrays
View the information that is shown about RAID arrays in block storage systems.
The following information is shown for each RAID array:
- Acknowledged
- Shows whether a user marked the status of a RAID array as acknowledged. An acknowledged status indicates that the status was reviewed and is either resolved or can be ignored. An acknowledged status is not used when the status of related, higher-level resources is determined.
- Available Capacity (%)
- The percentage of physical storage space that is unused on all the disk drive modules (DDMs) in the RAID array.
- Available Capacity (GiB)
- The total amount of physical storage space that is unused on all the DDMs in the RAID array.
- Available Written Capacity (GiB)
- For uncompressed RAID arrays, the available written capacity is the same as the available
capacity (available capacity here refers to available physical capacity) and represents the total
amount of unused storage capacity on all the DDMs in the RAID array.
For compressed RAID arrays, the available written capacity represents the amount of uncompressed data that is left unused in the array, of which can be written to the same array.
- Capacity (GiB)
- (Previously known as Physical Capacity) The total amount of data that can be stored at array. For compressed RAID arrays, after inline data compression takes place the capacity (capacity here refers to physical capacity) is smaller than the written capacity limit of the array because drive compression is used to reduce the size of the data.
- Compressed
- Shows whether the DDMs in the RAID array contain a built-in compression function that automatically compresses the data that is written to the drives.
- Compression Savings (%)
- For compressed RAID arrays, the amount and percentage of capacity that is saved by using drive compression.
- DDM Capacity (GB), DDM Capacity (GiB)
- The storage capacity of each disk drive module (DDM) in a RAID array, which is measured in GiB (gibibyte) and GB (gigabyte). 1 GiB is equal to approximately 1.074 GB. For example, if the capacity of a DDM is 135 GiBs, its value in GB is 146.
- DDM Class
- The technology type of the disk drives in the array, such as Solid-State Drive, NVMe SSD, Storage Class Memory, Flash, Fibre Channel (FC), SATA, and other types.
- DDM Speed (RPM)
- The revolutions per minute (RPM) of the DDMs in a RAID array. Examples: 5600, 7200, 10000, or 15000.
- Device Adapter Pair
- The device adapter (DA) pair that is associated with a RAID array. Available for DS8000 arrays only.
- Encryption
- Shows whether the DDMs in the RAID array are encrypted.
- Encryption Group
- The encryption group of a rank.
- Format
- The format of a RAID array. Examples: FB (fixed block), CKD (count key data). Available for DS8000 arrays only.
- Node
- For DS4000, DS5000, DS6000, and ESS storage systems, the name of the disk controller that is associated with the RAID array. For all other storage systems, the node to which a RAID array is associated.
- Pool
- The name of the pool in which a RAID array is a member.
- RAID Level
- The RAID level of an array, such as RAID 5, or RAID 10, or for distributed arrays, the RAID level is prefixed with “D”, such as DRAID 5.
- RAID State
- The state of a RAID array, based on the CLI value for the array. States include Online, Offline,
Degraded, Expanding, Synchronizing, Initializing, No Spare, and Unknown. Use the state to determine
the condition of the array, and if any actions must be taken. For example, a RAID array might have
one of the following states:
- Degraded
- A drive failed in the array and no spare is available. This state is a critical situation because if a second drive fails before the first one is replaced and rebuilt, all data on the RAID array is lost.
- Expanding
- A new drive is being added to the RAID array. When the expansion is complete, the capacity columns show the updated capacity of the array.
- No Spare
- A drive failed and was replaced automatically by the spare drive. Now, no spares are available for the array. Replace the failed drive as soon as possible, but the RAID array can sustain another drive failure without data loss.
- Synchronizing
- A drive failed in the array and is being replaced by the spare drive. The data that was on the failed drive is being rebuilt and is being written to the new drive, which used to be the spare drive. This state is a temporary critical situation because if a second drive fails before the data is rebuilt, data on the RAID array is lost.
- Rank
- The rank of which a RAID array is a member. A rank is a logically contiguous storage space. Typically, the relationship between arrays and ranks is a one-to-one relationship. Available for DS8000 arrays only.
- Status
- The status of a RAID array. Statuses include Normal, Warning, Error, and Unknown. Use the status to determine the condition of an array, and if any actions must be taken. For example, if an array has an Error status, take immediate action to correct the problem.
- Rank Group
- The rank group that is associated with a RAID array.
- Site
- The identifier of the array site for a RAID array. Available for DS8000 arrays only.
- Tier
- In Easy Tier, the performance capability of a tier is determined by the type of disks that the pool uses. Tier values might include Enterprise Tier, Nearline Tier, Tier 0 Flash, Tier 1 Flash, or Tier 2 Flash.
- Width
- The rank width of a RAID array. Available for DS8000 arrays only.
- Written Capacity Limit (GiB)
- (Previously known as Total Capacity) For uncompressed RAID arrays, the written capacity limit is
same as the capacity (capacity here refers to physical capacity) and represents the total storage
capacity of all the DDMs in the array.
For compressed RAID arrays, the written capacity limit is the maximum amount of uncompressed data that can be written to the array. This value is larger than the capacity (capacity here refers to physical capacity) as the drive compression is used to reduce the size of the data.