topic Re: disk slicing ADP - drive sizes in ONTAP Discussions

disk slicing ADP - drive sizes

MPERIYAK — Wed, 04 Jun 2025 23:12:11 GMT

I have read about ADP and it looks like the data is partiitoned automatically by the system. Does anyone have a guide on the approx space reserved by the system for ADP. Does it vary for SATA/SAS/SSD drives or what is the logic. I am just trying to calculate some usable space and need this info.

Re: disk slicing ADP - drive sizes

shatfield — Fri, 25 Sep 2015 12:30:43 GMT

It varies by configuration based on the number of drives being sliced. You can get the root slice size for a particular configuration from hardware universe.

Re: disk slicing ADP - drive sizes

sodakat — Fri, 25 Sep 2015 17:27:47 GMT

As was mentioned, HWU (http://hwu.netapp.com) is your friend, but here's a quick cheat-sheet from:

http://www.datacenterdan.com/blog/netapp-dataontap-83-adp-root-disk-slice-deep-dive

The root partition size is fixed and automatically set per controller. The actual amount will vary for the total of the root data partition between 430.9GiB (462.7GB) to 431.5GiB (463.3GB). The reason for this 0.13% fluctuation is due to the differing numbers of 4k blocks available with different spindle counts. Of course, the OCD in me wishes it was always just 450GB for a nice round number!

The way that root partition is parceled out is then based upon the number of disk drives with root partitions, calculating for the appropriate RAID level and hot spares as well. Here are the common disk configurations and their corresponding root disk sizes:

FAS2520 (12 Internal HDD)
FAS2552/4 (24 Internal HDD)
FAS2552/4 (20 Internal HDD)
FAS8000 AFF (24 SSD)
FAS8000 AFF (36 SSD)
FAS8000 AFF (48 SSD)

144GiB per root slice
54GiB per root slice
62GiB per root slice
54GiB per root slice
31GiB per root slice
22GiB per root slice