StorSimple 8k series as a backup target?

19 December 2016

After a conference call with Microsoft Azure StorSimple product team, they explained:

•  “The maximum recommended full backup size when using an 8100 as a primary backup target is 10TiB. The maximum recommended full backup size when using an 8600 as a primary backup target is 20TiB”
• “Backups will be written to array, such that they reside entirely within the local storage capacity”

Microsoft acknowledge the difficulty resulting from the maximum provisionable space being 200 TB on an 8100 device, which limits the ability to over-provision thin-provisioned tiered iSCSI volumes when expecting significant deduplication/compression savings with long term backup copy job Veeam files for example.

Conclusion

• When used as a primary backup target, StorSimple 8k devices are intended for SMB clients with backup files under 10TB/20TB for the 8100/8600 models respectively
•  Compared to using an Azure A4 VM with attached disks (page blobs), StorSimple provides 7-22% cost savings over 5 years

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15 December 2016

On 13 December 2016, Microsoft announced the support of using StorSimple 8k devices as a backup target. Many customers have asked for StorSimple to support this workload. StorSimple hybrid cloud storage iSCSI SAN features automated tiering at the block level from its SSD to SAS to Azure tiers. This makes it a perfect fit for Primary Data Set for unstructured data such as file shares. It also features cloud snapshots which provide the additional functionality of data backup and disaster recovery. That’s primary storage, secondary storage (short term backups), long term storage (multiyear retention), off site storage, and multi-site storage, all in one solution.

However, the above features that lend themselves handy to the primary data set/unstructured data pose significant difficulties when trying to use this device as a backup target, such as:

• Automated tiering: Many backup software packages (like Veeam) would do things like a forward incremental, synthetic full, backup copy job for long term retention. All of which would scan/access files that are typically dozens of TB each. This will cause the device to tier data to Azure and back to the local device in a way that slows things down to a crawl. DPM is even worse; specifically the way it allocates/controls volumes.
• The arbitrary maximum allocatable space for a device (200TB for an 8100 device for example), makes it practically impossible to use the device as backup target for long term retention.
  • Example: 50 TB volume, need to retain 20 copies for long term backup. Even if change rate is very low and actual bits after deduplication and compression of 20 copies is 60 TB, we cannot provision 20x 50 TB volumes, or a 1 PB volume. Which makes the maximum workload size around 3TB if long term retention requires 20 recovery points. 3TB is way too small of a limit for enterprise clients who simply want to use Azure for long term backup where a single backup file is 10-200 TB.
• The specific implementation of the backup catalog and who (the backup software versus StorSimple Manager service) has it.
• Single unified tool for backup/recovery – now we have to use the backup software and StorSimple Manager, which do not communicate and are not aware of each other
• Granular recoveries (single file/folder). Currently to recover a single file from snapshot, we must clone the entire volume.

In this article published 6 December 2016, Microsoft lays out their reference architecture for using StorSimple 8k device as a Primary Backup Target for Veeam

There’s a number of best practices relating to how to configure Veeam and StorSimple in this use case, such as disabling deuplication, compression, and encryption on the Veeam side, dedicating the StorSimple device for the backup workload, …

The interesting part comes in when you look at scalability. Here’s Microsoft’s listed example of a 1 TB workload:

This architecture suggests provisioning 5*5TB volumes for the daily backups and a 26TB volume for the weekly, monthly, and annual backups:

This 1:26 ratio between the Primary Data Set and Vol6 used for the weekly, monthly, and annual backups suggests that the maximum supported Primary Data Set is 2.46 TB (maximum volume size is 64 TB) !!!???

This reference architecture suggests that this solution may not work for a file share that is larger than 2.5TB or may need to be expanded beyond 2.5TB

Furthermore, this reference architecture suggests that the maximum Primary Data Set cannot exceed 2.66TB on an 8100 device, which has 200TB maximum allocatable capacity, reserving 64TB to be able to restore the 64TB Vol6

It also suggests that the maximum Primary Data Set cannot exceed 8.55TB on an 8600 device, which has 500TB maximum allocatable capacity, reserving 64TB to be able to restore the 64TB Vol6

Even if we consider cloud snapshots to be used only in case of total device loss – disaster recovery, and we allocate the maximum device capacity, the 8100 and 8600 devices can accommodate 3.93TB and 9.81TB respectively:

Conclusion:

Although the allocation of 51TB of space to backup 1 TB of data resolves the tiering issue noted above, it significantly erodes the value proposition provided by StorSimple.