About adding and removing disks

Why you might add or remove disks

You might want to add disks to the appliance to increase available disk space, to add a hot spare, or to replace a failed disk. You might want to remove a disk from your appliance because you want to use it in another appliance, because it has failed, or because it is producing excessive error messages.

Adding new and previously used disks

In most cases, the disk you add will be a new disk; that is, the disk has never been used.

If the disk you want to add to the appliance was previously used by another appliance or a Network Appliance filer, make sure that you unfail the disk before you begin. To unfail the disk, boot the appliance from a system boot diskette into Maintenance mode, then use the disk unfail command.

If you want to add a new disk to an existing system, first add the disk as a hot spare. Then, if you want the disk to be used as a data disk, promote the disk to be part of the file system.

When to add or remove disks in external disk platforms

The Appliance Manager enables you to add or remove a single disk from the system without interrupting service to your users. However, during the procedure, the appliance operates in proxy-only mode. That is, the appliance proxies requests on behalf of users by retrieving the objects from the source server. No new objects are saved to the cache, and no objects in the cache are served to users. Because users might notice slower performance during this time, it is a good idea to plan to add or remove disks when you expect the load on the appliance to be light.

If you are adding more than one disk or a new disk shelf to your system

If you are adding several disks or a new disk shelf to your system, the process might be faster if you shut down the system. If you shut down the system, you can add all the disks at once, then reboot the system. Otherwise, you must add the disks one at a time using the Appliance Manager.

If you must remove more than one disk from your system

If you must remove more than one disk from the appliance, Network Appliance recommends that you remove and replace that disk before proceeding to remove another disk. If you remove more than one disk at a time from the appliance, the appliance will not be able to rebuild the data from the remaining disks. You will have to reinstall both the file system and the appliance software in that case.

If you are performing disk operations online

If you are performing disk operations online, you can perform only one operation at a time. The appliance does not allow you to begin a new disk operation if a previous disk operation is incomplete.

Using hot spares in external disk platforms

If you want to prevent loss of service time, you can add one or more hot spare disks. When a data disk on the appliance fails, a hot spare automatically replaces it without a system shutdown.

To determine whether your appliance contains a hot spare, see the Disk - Management page (Maintenance tab > Disk > Management) of the Appliance Manager. This page lists all appliance disks and indicates whether a disk is a parity, data, or spare disk.

You can add more hot spare disks to the system at any time, as long as disk slots are available.