Friday, May 18, 2018

Netapp Terminologies & Concepts


aggregate
 physical disk, raw space, doesn't hold data
volumes
 these are inside aggregates, it holds the data
LUN
 logical repressentation of storage





hot spare disks
A hot spare disk is a disk that is assigned to a storage system but is not in use by a RAID group. It does not yet hold data but is ready for use.

If a disk failure occurs within a RAID group, Data ONTAP automatically assigns hot spare disks to RAID groups to replace the failed disks.
What disks can be used as hot spares?
A disk must conform to certain criteria to be used as a hot spare for a particular data disk.
For a disk to be used as a hot spare for another disk, it must conform to the following criteria:
It must be either an exact match for the disk it is replacing or an appropriate alternative.
The spare must be owned by the same system as the disk it is replacing.
CIFS Oplocks
- CIFS oplocks reduce network traffic and increase the storage performance.
- Its working like caching of read-ahead, write-behind, and lock information.
- you can enable/disable CIFS oplocks for the individual volume or qtree.
- In the database application we should turn off the CIFS oplocks - when you
  handling critical data and can't afford the data loss.
- Otherwise, you can on  CIFS oplocks options.
spindles
- # of spindles = # of physical disks
- there is one spindle in each physical disk
- more spindles means more disks
- more spindles for better performance in terms of I/O! (solution to sata slowness)
- more spindles will process more data at a time
provisioning
- thin provision is space reservation
- thick provisioning is no space reservation







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