StarWind iSCSI SAN V6 Released

Although it has been available for about a month, the next major release of the StarWind iSCSI target is here! Some of the biggest features include (taken from here):

High availability:
– 3-node HA configuration. Synchronous mirroring between 3 nodes of an HA storage cluster. Such storage architecture ensures higher uptime and higher performance compared to a 2-node HA configuration.
– HA device nodes manager. You can add, remove, or switch nodes of HA cluster on the running device instead of the creation of a new HA device from scratch.
– An HA device can now use other types of StarWind devices (deduplicated, thin-provisioned IBV, or DiskBridge devices) for storing data. Thus, you can apply deduplication, thin provision, snapshot technologies, etc., for the data stored on the HA device. Experimental feature.
– ALUA. Asymmetric logical unit access is required for cases when individual nodes use very different by performance metrics storage types like SATA on one node and SSD on another. With ALUA enabled most of I/Os are served by faster node resulting less latency for I/O intensive applications.

– Asynchronous replication to remote iSCSI Target over WAN as an experimental feature.
– Data deletion support (experimental feature). Unused data blocks are overwritten by the new actual data.
– Memory usage reduced by 30%. When the dedupe block size is set to 4kb, 2MB of memory are required per 1GB of stored data.

iSCSI Boot:
– StarWind can be used to build and configure environment for iSCSI boot.
– Two modes added for Snapshot and CDP device: redirect on write and redirect on write with discard. These options can be used for booting multiple clients from one image.

Event notifications:
– Free space low watermarks are now reported for thin-provisioned and deduplicated volumes.

Backup Plug-in for Hyper-V virtual machines:
– Incremental backup and delta data saving features added.

Backup Plug-in for ESX virtual machines (experimental feature):
– Full and incremental backup of virtual machines.
– ESX VMs management.
– Backup archives are saved in the native VMware format – VMDK.


The current version is 6.0.4768 – the biggest reason for me to upgrade to this version was the deduplication deletion support. Previously, a deduped device would continue to grow in size when data was deleted as it did not keep track of unused blocks. This would cause the .spdata file to grow rather large, especially if you do a storage VMotion or have a lot of changing data. Here’s a snapshot of the dedupe device creation:

The deletion support in its current form (still an ‘experimental feature’) will now overwrite unused blocks with actual data – keep in mind, though that the container files on the StarWind server will not shrink in size – that is a feature that will likely show up in a future release.

Currently, I’m “using” around 270GB of storage which is only occupying ~68GB on disk. Bear in mind that this ratio could be better – but I am currently running both Server 2008 R2 AND Server 2012 VMs.

For best performance, set deduplication block size to 4K and do NOT use thin-provisioning on top of deduplicated devices.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.