Product specifications

Managing Storage Managers

If you do not have a replacement for a failed or failing Storage Manager, Avid recommends that you physically leave

it in the Engine (ISIS | 7500 only), even after it has been removed from the file system. Proper airflow cannot be

guaranteed if a Storage Manager slot is left open.

Before you remove an Avid ISIS Storage Manager from the network, you must redistribute the data stored on the

Storage Manager to other Storage Managers in the system. The redistribution occurs before you physically remove

the Storage Manager, and the process entails moving data to the remaining drives within the Storage Group. Once

you redistribute the data, you add a new Storage Manager to the system and then perform a redistribution again to

place data onto the new Storage Manager.

If you physically remove a Storage Manager from the shared storage network before redistribution is

complete, data loss can occur.

Maintain an unused block of storage equivalent to one Storage Manager within the Storage Group to allow

redistribution from a failing Storage Manager to other Storage Managers within the group.

If possible, redistribute data while the drive is experiencing problems but has not yet been removed from the system.

This allows the Storage Manager having problems to participate in the redistribution process by offering its data to

both clients and to other Storage Managers.

Often the Storage Manager is still functional, but its performance is slightly degraded — for example, the

Storage Manager might have an unrecoverable error on one of its disks, or it might have long I/O times.

If the Storage Manager fails, or if it has been removed from the system, you can perform a redistribution from the

mirrored or RAID locations associated with the Storage Manager. However, if any other mirrored location

experiences a failure while performing a redistribution, the system can lose data.

If the failed Storage Manager was part of an unprotected Workspace, data loss is likely.

Consider the following when planning a redistribution:

• A one-to-one replacement of Storage Managers might leave you with less storage space in the Storage Group

than you require. Instead, plan for using more Storage Managers than you need for storage and bandwidth for

each Storage Group. This way, you can keep an optimal amount of available storage space allocated to the

Storage Group. This allows you to quickly perform redistribution, rather than attempting a redistribution with

only one spare Storage Manager.

• In general, the removal of a Storage Manager is quicker than an addition. This is because all of the other

Storage Managers in a Storage Group participate in redistribution by moving a copy of any block held by the

Manager to another location. The more Storage Managers in the Storage Group, the more the workload is

shared. A single Storage Manager addition is slower than a removal because the Storage Manager receiving the

data acts as a limiting factor for the redistribution.

• When you add a new Storage Manager to the Avid ISIS file system and then add it to a Storage Group, the

system redistributes data from the existing drives in the Storage Group to the new Storage Manager. This

redistribution maintains all previously stored data, but the data might not reside on the same Storage Managers.

The following steps list the actions necessary for removing a Storage Manager:

1. Identify the Storage Manager to replace.

2. Remove the Storage Manager from the Storage Group.

3. View the status of the redistribution and wait for redistribution to finish.

4. Unbind the Storage Manager from the Storage Group.

5. Physically remove and replace the Storage Manager.