Configuring a Volume Set for Concurrent Writes

Updated Sept. 14, 2016

Overview
With the default settings, a Volume Set configured on a XenData Server system will write to only one Volume at a time. The maximum sustainable transfer rate per Volume Set is limited to that of an LTO or Optical Disc Archive drive. By enabling concurrent writes, files allocated to a single Volume Set may be written to the XenData disk cache and then written to two or more Volumes, as the cartridges within the multiple Volumes come available. This increases the potential sustainable transfer rate for all files allocated to a specific Volume Set. Concurrent writes are enabled by editing the XenData State File and adding a ConcurrentWrites attribute for each applicable Volume Set.

Adding the Concurrent Writes Attribute

1. Create the Volume Set or Volume Sets for which concurrent writes will be enabled. Configure the Volume Set and set up replication as required.
2. Ensure that the archive system is idle and stop the XenData Archive Series service.
3. Edit the XenDataState.xml file which is located in the C:\WINDOWS\system32 folder as described below.
4. Restart the XenData Archive Series service.
5. Add Volumes to the Volume Sets using the Archive Management Console.

Edit Instructions
A typical section from the XenDataState.xml file that defines the configuration for a Volume Set is shown below:

– <VolumeSetSet>
– <VolumeSet
Identity="486ABCAC-00000000" Name="486ABCAC-00000000" MediumType="Tape" Attribute="Rewritable" Replicas="1" Compressed="0" Deferred="0" GroupedReplicas="0" WriteIfNoMediaAvailable="0" UnusedCapacity="0.02" NewVolumeCapacity="0.95">
<Backup Immediate="0" Periodic="0" Volume="0" Timed="0" /> </VolumeSet>
– </VolumeSetSet>

The XML file should be edited as shown below to add a concurrent writes attribute:

– <VolumeSetSet>
– <VolumeSet
Identity="486ABCAC-00000000" Name="486ABCAC-00000000" MediumType="Tape" Attribute="Rewritable" Replicas="1" ConcurrentWrites="2" Compressed="0" Deferred="0" GroupedReplicas="0" WriteIfNoMediaAvailable="0" UnusedCapacity="0.02" NewVolumeCapacity="0.95">
<Backup Immediate="0" Periodic="0" Volume="0" Timed="0" /> </VolumeSet>
– </VolumeSetSet>

It is important that the ConcurrentWrites attribute is added immediately after the Replicas attribute. The value for ConcurrentWrites attribute determines the number of Volumes that are written concurrently.

Applicable Operating Systems

• Windows Server 2012 R2
• Windows Server 2016
• Windows Server 2019

Applicable XenData Software
This technical note is applicable to:

• Version 6 – Server Editions of Archive Series software
• Version 7 – Server Editions of Archive Series software including the Cloud File Gateway