Storage Replica: Known Issues

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Updated: November 19, 2015

This section discusses known issues with Storage Replica in Windows Server 2016 Technical Preview.

After removing replication, disks are offline and you cannot configure replication again

In Windows Server 2016 Technical Preview, you may be unable to provision replication on a volume that was previously replicated or may find un-mountable volumes. This may occur when some error condition prevents removal of replication or when you reinstall the operating system on a computer that was previously replicating data.

To fix, you must clear the hidden Storage Replica partition off the disks and return them to a writeable state. Previously this required complex DISKPART steps but Windows Server 2016 Technical Preview introduces a simple cmdlet named Clear-SRMetadata.

  • To remove all orphaned Storage Replica partition databases slots and remount all partitions, use the –AllPartitions parameter as follows:

    Clear-SRMetadata -AllPartitions

  • To remove all orphaned Storage Replica log data, use the –AllLogs parameter as follows:

    Clear-SRMetadata -AllLogs

  • To remove all orphaned failover cluster configuration data, use the –AllConfiguration parameter as follows:

    Clear-SRMetadata -AllConfiguration

  • To remove individual replication group metadata, use the –Name parameter and specify a replication group as follows:

    Clear-SRMetadata –Name RG01 –Logs -Partition

The server may need to restart after cleaning the partition database; you can suppress this temporarily with –NoRestart but you should not skip restarting the server if requested by the cmdlet. This cmdlet does not remove data volumes nor data contained within those volumes.

During initial sync, see event log 4004 warnings

In Windows Server 2016 Technical Preview, when configuring replication, both the source and destination servers may show multiple StorageReplica\Admin event log 4004 warnings each during initial sync, with a status of “insufficient system resources exist to complete the API”. You are likely to see 5014 errors as well. These indicate that the servers do not have enough physical memory (RAM) to perform both initial synchronization as well as run workloads. Either add RAM or reduce the used RAM from features and applications other than Storage Replica.

When using guest clusters with Shared VHDX and a host without a CSV, virtual machines stop responding after configuring replication

In Windows Server 2016 Technical Preview, when using Hyper-V guest clusters for Storage Replica testing or demonstration purposes, and using Shared VHDX as the guest cluster storage, the virtual machines stop responding after you configure replication. If you restart the Hyper-V host, the virtual machines start responding but replication configuration will not be complete and no replication will occur.

This behavior occurs when you are using fltmc.exe attach svhdxflt to bypass the requirement for the Hyper-V host running a CSV. Use of this command is not supported and is intended only for test and demonstration purposes.

The cause of the slowdown is a by-design interoperability issue between the new Storage QoS feature in Windows Server 2016 Technical Preview and the manually attached Shared VHDX filter. To resolve this issue, disable the Storage QoS filter driver and restart the Hyper-V host:

SC config storqosflt start= disabled

Removing disks from Available Storage prevents them from use again

In Windows Server 2016 Technical Preview, when using Failover Cluster Manager to remove available storage asymmetric shared disks, you can no longer add some of them back later. They do not appear in the Add Disks view.

Use Clear-ClusterDiskReservation to make these disks eligible to Available Storage. To prevent the issue, only remove disks when they show as Online and owned by the cluster nodes that physically attach to them.

Cannot configure replication when using New-Volume and differing storage

When using the New-Volume cmdlet along with differing sets of storage on the source and destination server, such as two different SANs or two JBODs with differing disks, you may not be able to subsequently configure replication using New-SRPartnership. The error shown may include:

Data partition sizes are different in those two groups

Use the New-Partition cmdlet to create volumes and format them instead of New-Volume, as the latter cmdlet may round the volume size on differing storage arrays. If you have already created an NTFS volume, you can use Resize-Partition to grow or shrink one of the volumes to match the other (this cannot be done with ReFS volumes). If using Diskmgmt or Server Manager, no rounding will occur.

Cluster disks do not come online

When using Windows Failover Cluster with Storage Replica, storage may not come online and there may be indications of deadlocks or bugchecks. This issue is caused by an interoperability bug with the Windows Search service. As mentioned in the provisioning steps, you must stop and disable this service in Windows Server 2016 Technical Preview.

Delegation

Administrative delegation of Storage Replica does not work correctly in Windows Server 2016 Technical Preview via the SRDelegation cmdlets. Do not attempt to configure delegation with these cmdlets.

Test-SRTopology on non-US Region servers

The Test-SRTopology cmdlet will not operate correctly when run on servers that are configured with a different region than US English, such as the one which uses commas instead of periods for decimal separators. To use Test-SRTopology , temporarily change the region to US before running the cmdlet, then change it back when finished.

Get-SRGroup and Get-SRPartnership errors

The Get-SRGroup and Get-SRPartnership cmdlets return an error when you do not provide any parameters and there are not groups or partnerships on the server.

PS C:\> get-srgroup
get-srgroup : Failed to find replication group on computer.
At line:1 char:1
+ get-srgroup
+ ~~~~~~~~~~~
    + CategoryInfo          : InvalidData: (MSFT_WvrAdminTasks:root/Microsoft/...T_WvrAdminTasks) [Get-SRGroup], Cim
   Exception
    + FullyQualifiedErrorId : Windows System Error 6,Get-SRGroup

This behavior is a regression from Technical Preview 3. As a workaround, use the –Name * parameter and argument, such as Get-SRGroup –Name *.

Stretch cluster failover and CSV move may take minutes

When moving replicated CSVs between sites or if there is an unplanned failover to another site, the source CSV may take up to 3 minutes to come online. This behavior is a regression from Technical Preview 3. There is no workaround.

See Also