Rocket Storage Monthly: The future of TimeFinder with VMAX3
Earlier this year we spoke about the different types of TimeFinder local replication present within the EMC VMAX. However, as we move through 2015 and into 2016 we will see a new flagship making its way into datacenters. EMC is planning to replace the VMAX with a new model called the VMAX3. This new member of the Symmetrix family will bring a variety of changes and improvements, and one such improvement of interest is the new version of TimeFinder.
Out with the old: Farewell TimeFinder Snap
The VMAX3 will ship with the new HYPERMAX OS, starting with version 5977. The version number here reminds us of its evolutionary status over the VMAX’s Enginuity 5876. Thankfully, HYPERMAX 5977 retains many abilities that VMAX operators are familiar with. Through emulation support, TimeFinder Clone and VP Snap will still be supported and can be created and managed identically to Enginuity 5876. Concurrent session count, source-target pairings and all other details about Clone and VP Snap will remain just as they are on VMAX.
On the other hand, there is one feature deprecation of note as the aging TimeFinder Snap is absent from HYPERMAX. VP Snap is largely a superior replacement to Snap and it therefore should not be surprising to find that Snap will no longer be with us. For those who are still using Snap, EMC states that it will be offering services for those users that need help converting to a newer TimeFinder type.
In with the new: Introducing TimeFinder SnapVX
TimeFinder SnapVX, the newest iteration of TimeFinder that will be found on the VMAX3, is going to be a major change for the better in the way that we interact with TimeFinder. Performance enhancements and removal of limitations from previous TimeFinder versions will benefit many, but the most exciting ability of SnapVX is that no longer will point-in-time snapshots need to be thought of in traditional Source-and-Target pairs. SnapVX will be target-less, that is, all that is needed to create a point in time snapshot is to specify the source volume(s) and the name of the new snapshot. Here are some SnapVX highlights to expect:
- Target-less snapshots – Create a point in time with only sources and snapshot name specified
- Snapshot mapping – Attach snapshots to target LUNs to expose the data to hosts
- Writes to target LUNs with attached snapshots do not alter the point in time snapshot. These remain unmodified since snapshots are never directly exposed to hosts
- NoCopy and Copy Backups – To make a full copy of a volume, attach a snapshot to a target volume in Copy mode. When the copy is complete then the target can be detached from the snapshot to have a full clone.
- Up to 256 snapshots per source volume
- Up to 1024 target volumes can be linked to the snapshots of a source volume
- Defining – Target volumes in NoCopy mode can have track pointers to the data residing on the Storage Resource Pool (SRP) rather than being redirected from the source volume and snapshots. This improves the performance of read operations.
- Cascading snapshots from targets is allowed once the target is fully defined or copied
- No limitation on the amount of cascading of snapshots and targets as long as the 256 snapshot count and 1024 target volume count are not exceeded
- Cascaded targets can be restored from snapshots as long as they are in Copy mode and are fully copied
- One-to-many snapshot deltas where changed data is written to an SRP only once but can be used by all snapshots taken before that point in time. This is the same space efficient technique used in Snap VP.
- Redirect-on-write – Writes to a source that has snapshots will be accepted asynchronously and placed in a new location in the SRP. The source volume will point to this data while the snapshots will continue to point to the original data.
- Asynchronous Copy-on-First-Write – In certain situations, to prevent a write from being directed to a lower storage tier, a source volume’s original data may instead be copied to a lower tier to allow the new source data to reside in the higher tier.
- Storage group snapshots – Rather than using a device file or composite group, users can now specify the creation of a snapshot for an entire storage group of one or more hosts.
In addition to the highlights, you can read through EMC’s entire technical document on SnapVX here: http://www.emc.com/collateral/technical-documentation/h13697-emc-vmax3-local-replication.pdf
What do you think about the changes to TimeFinder for the VMAX3? Feel free to discuss this in the comments section below.