Why am I getting a SPARES LOW warning?
Applies to
- Data ONTAP 8 7-mode
- Spares
Answer
ONTAP triggers SPARES LOW
warning when the available spare disks goes below 2.
Spares are considered per system not per loop or SAS domain. When considering usable spares however, factors such as checksum (512 vs 520), type (FC, SATA, SAS), and pools (in case of Syncmirror) will factor in.
Consider the following:
- A filer has two drive capacities, 4TB and 6TB, with three spare 4TB drives.
- All of the existing aggregates are made up of 4TB drives
- Now a new shelf with 6TB drives are added.
- A new aggregate was created using all of the 6TB drives.
- A SPARES LOW error is sent, because even though there are three spares available, all of the 6TB drives have been used and a 4TB spare cannot be used to reconstruct 6TB disk.
- Consider the same case as in 1, but in a different situation: instead of adding the new shelf of 6TB drives, users add the remaining three 4TB drives to the aggregate. No SPARES LOW error will be sent, as 6TB drives can serve as spares for 4TB drives.
- Additionally 15K RPM drives can still stand in for 10K RPM drives. For more information, see How you can use disks with mixed speeds in the same aggregate
- You may get SPARES LOW when you have raidgroups with at least one 15K RPM disk and only 10K RPM sparedisks. In such cases;
- You can unmix the disks with the
disk replace
command. - Allow ontap to mix the disks RPM-wise by setting the corresponding option to OFF as discussed in the above article.
- You can unmix the disks with the