SHIFT-WIKI - Sjoerd Hooft's InFormation Technology
This WIKI is my personal documentation blog. Please enjoy it and feel free to reach out through blue sky if you have a question, remark, improvement or observation. See below for the latest additions, or use the search or tags to browse for content.
Replace a Disk on a NetApp Filer
Summary: How to replace a failed disk on a Netapp Filer.
Date: Around 2015
Refactor: 7 March 2025: Checked links and formatting.
If you need to replace a disk in one of your netapp filers (for example because it is faulty) you can use the disk replace command:
disk replace start [-f] [-m] <disk_name> <spare_disk_name>
-f: skip confirmation-m: allows mixing disks with different characteristics. It allows using the target disk with rotational speed that does not match that of the majority of disks in the aggregate. It also allows using the target disk from the opposite spare pool.
The disk replace command uses Rapid RAID Recovery to copy data from the specified file system disk to the specified spare disk. At the end of that process, roles of disks are reversed. The spare disk will replace the file system disk in the RAID group and the file system disk will become a spare.
The process can be stopped with:
disk replace stop <disk_name>
NetApp Data Planning
Summary: A show and tell about several data functions on NetApp Filers.
Date: Around 2015
Refactor: 7 March 2025: Checked links and formatting.
With the introduction of all kind of options in their filers NetApp provides several ways to plan for your data consumption. In this article I'll discuss a few of the most confusing options and clarify them and their interaction with each other by showing an example.
Change NetApp Filer IP Address And Hostname
Summary: How to change the IP address on a Netapp Filer.
Date: Around 2015
Refactor: 7 March 2025: Checked links and formatting.
Changing the IP address of a NetApp filer is easy enough. The ONTAP operating system allows the use of the ifconfig command which is not that hard to use. What is a little bit harder is making sure the filer keeps working if it has a partner for failover functionality. My approach changes the IP address, the hostname and all other options I could find that are necessary to successfully change the IP information without a reboot. By editing the /etc/rc and the /etc/hosts files you can change the current configuration and make sure the changes are persistent over reboots. Afterwards a few settings need to change as well.
NetApp - Designing your disks, raids and aggregates
Summary: Keep this in mind when designing storage on a Netapp Filer.
Date: Around 2015
Refactor: 7 March 2025: Checked links and formatting.
When configuring a NetApp and designing the aggregate size there is something really important to keep in mind. So bear with me while I write it down. In a NetApp filer are disks. Disks themselves are point of failures, and that's why we use RAID. In this story I'll keep to raid_dp, which stand for raid double parity. This means that in each raid set that is configured two disks can fail before you're screwed. However, since NetApps work with WAFL (write anywhere file layout) you as a administrator don't work with disks and RAID, you work with aggregates and volumes. Also consider, that if you add disks to an aggregate they are automatically added to the RAID until it is full and a new RAID set will be created. Now a raid_dp set can contain up to 28 disks, but the default is 16. That means that if you have 20 disks, and don't change the default two RAID sets will be created, one containing 16 disks, and one containing 4 disks. That means two things: First, you loose 4 disks to parity, two to spare and you only keep 14 disks left for actual storage. Second, large RAID sets operate faster than small raid sets. That is because more disks can write at the same time in a large raid set (sales will tell you they're both evenly fast but ask any netapp engineer and he'll tell you the same.). So this meams you get an aggregate that's slow, since it will be as fast as the slowest RAID set. Than a final note, keep in mind the maximum size for an aggregate on a NetApp ONTAP 7.3 filer is 16 TB. So keep all this in mind when you're designing your aggregates.
note: You cannot remove disks from an aggregate! This is very important, so grow your aggregates with caution, it's easy to grow, impossible to shrink. If you've grown your aggregate too much then you'll need to destroy it to regain those spares.