When multiple AFTDs are in the same pool, you won't have control over what backup set goes where and if there is concern that AFTD may fiil, then it is better to use bigger one.
I forgot to mention the space management of the AFTD device. There is a configurable setting for determining at what capacity the NetWorker software should stop writing to an AFTD spans from 1 to 100%. Setting the value to 0 or leaving the attribute empty in the AFTD Percentage Capacity attribute is equivalent to a setting of 100%. This means that the entire capacity of the filesystem can be used for the AFTD volume.
When set, the AFTD Percentage Capacity attribute is used to declare the volume full and to calculate high/low watermarks. Whenthe percentage capacity attribute is modified, mount and re-mount the volume for the new settings to take effect. The level watermark is calculated based on the percentage of restricted capacity, not on the full capacity of the filesystem.
There is a feature called "AFTD load balancing", where you can adjust the target and max sessions attributes per device to balance the data load for simultaneous sessions more evenly across available devices. These parameters specify the maximum number of save sessions to be established before the NetWorker server attempts to assign save sessions to another device.
For AFTDs, all volumes, depending on the selection criteria (pool settings), choose the AFTD with the least amount of data written to it, and join sessions based on the device's target and max sessions. If the number of sessions being written to the first device exceeds the target sessions setting, another AFTD is considered for new backup sessions and is selected from the remaining suitable AFTDs. The AFTD that is selected will be the AFTD with the least amount of NetWorker data written to it. The least amount of data written is calculated in bytes (not by percentage of disk space used) and only bytes that were written by NetWorker are counted.
ble1
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14.4K Posts
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October 20th, 2012 05:00
When multiple AFTDs are in the same pool, you won't have control over what backup set goes where and if there is concern that AFTD may fiil, then it is better to use bigger one.
Bebo2k
544 Posts
0
October 20th, 2012 14:00
I forgot to mention the space management of the AFTD device. There is a configurable setting for determining at what capacity the NetWorker software should stop writing to an AFTD spans from 1 to 100%. Setting the value to 0 or leaving the attribute empty in the AFTD Percentage Capacity attribute is equivalent to a setting of 100%. This means that the entire capacity of the filesystem can be used for the AFTD volume.
When set, the AFTD Percentage Capacity attribute is used to declare the volume full and to calculate high/low watermarks. Whenthe percentage capacity attribute is modified, mount and re-mount the volume for the new settings to take effect. The level watermark is calculated based on the percentage of restricted capacity, not on the full capacity of the filesystem.
Hope this helps you.
Ahmed Bahaa
Bebo2k
544 Posts
0
October 20th, 2012 14:00
Hi Andrew,
There is a feature called "AFTD load balancing", where you can adjust the target and max sessions attributes per device to balance the data load for simultaneous sessions more evenly across available devices. These parameters specify the maximum number of save sessions to be established before the NetWorker server attempts to assign save sessions to another device.
For AFTDs, all volumes, depending on the selection criteria (pool settings), choose the AFTD with the least amount of data written to it, and join sessions based on the device's target and max sessions. If the number of sessions being written to the first device exceeds the target sessions setting, another AFTD is considered for new backup sessions and is selected from the remaining suitable AFTDs. The AFTD that is selected will be the AFTD with the least amount of NetWorker data written to it. The least amount of data written is calculated in bytes (not by percentage of disk space used) and only bytes that were written by NetWorker are counted.
Ahmed Bahaa