NetApp Basics

 

Root Volume:

Root volume holds all the ONTAP files. It always preferred to separate the root volume from Data volumes. Better options to restrict the root volume to just 2 disks. This enables faster reconstruction times in case of a disk failure on the root volume.

Volume Snapshot Reserve:

·     The default snapshot reserve space is 20% of the volume size. As snapshot copies need space, they consume space in the snap reserve area. The snapshot copies will start to consume the volume space if it is getting filled up, Better options to enable the autodelete snapshot options to avoid volume filed up and write error issue.

Aggregate Reserve:

·      Default Aggregates are created by default with 5% of reserve space.

The aggregate space is calculated as below:

Aggregate usable size = disk capacity X number of disks X 0.90 X 0.95

    Thumb rule of 2 disk hot spares is applied for every 30 disks

     Snapshot reserve default 5% for aggregate and 20% for flexvolume

    Snapshot for LUNS is subject to space reservations. It might be null or fractional

WAFL (write anywhere file layout) overhead:

·         WAFL reserves approximately 10% of space for performance reason and metadata.

Spare Disks allocation:

·         It depends upon your space and data protection calculation.

As per NetApp suggestion:

On NetApp storage, disk failures automatically trigger parity reconstructions of affected data onto a hot standby (spare) disk, assuming that a spare disk is available. If no spare disks are available, self-healing operations are not possible. The system will run in degraded mode 

Calculate the disk size:

·      Storage hard disk is using the base system and software is using the base 2 system.

Hard disk manufacturers assume Base 10 System Killo = 10 the power of 3

File system assumes Killo = 2th power of 10 = 2X2X2X2X2X2X2X2X2X2=1024

1TB hard disk is actual size :

1000,000,000 bytes/ 1,073,741,824  = .9313 x 1000 = 931.3 GB