Tag: replication

Rubrik makes instant recovery easy everywhere. As I wrote four months ago, it only takes a few clicks to bring a previous version of any protected VM into production. In 2.0, the great folks at Rubrik enhanced this capability with replication.

Replication is a word that means many things to many people and could quickly get abused in comparisons. In our previous data protection solution, replication of backups was limited to scheduled jobs and practically meant our off-site backups were anywhere from 3 hours (best case) to 48 hours (worst case) old, with no guarantees.

Rubrik takes a refreshingly different tactic. In its policy-based world, backups are driven by SLAs (gold, silver, bronze, etc), which are defined by frequency and retention of snapshots. Replication is married to these policies and is triggered upon the completion of VM backups.

For example, this morning one of our mission-critical SQL servers in our Gold Repl SLA domain started a backup job at 6:35am and completed that job one minute later at 6:36am. Gold Repl takes snapshots every 4 hours, keeps those hourlies for 3 days, and then keeps dailies for a month. As the “Repl” denotes, it also replicates and retains 3 days of those backups at another site. Oh, and as the cherry on top, it additionally archives the oldest backups to Amazon S3. Pretty comprehensive, eh?

repl_source_snap

Storage Technology Virtualization

On Monday I had the privilege of participating in an unplanned recovery drill after maintenance on our site UPS and generator tripped over itself (four times). Needless to say, a lot of our infrastructure doesn’t take too kindly to unexpected darkness, and its lack of choreography means that things come up out of order. But that’s not the focus here, just the context. Most everything was restored in relatively short order thanks to good documentation of this nature:

  1. Confirm power is reliable and not likely to fail again in the immediate future
  2. Power on network switches (core, rack, etc)
  3. Power on storage array(s) (HP, EMC, etc)
  4. Power on virtualization hosts (ESXi, Hyper-V)
  5. Connect to each virtualization host directly (vSphere Client to hostname / RDP to Hyper-V Console)
  6. Confirm presence of all storage (LUNs, datastores, CSVs)
  7. Confirm recognition/identities of hosted virtual machines (out-of-order boot may see VMs as “unknown”)
  8. If any storage is missing or VMs “unknown”, reboot hosts to confirm storage accessibility
  9. If VMs auto-power on, force power off to prevent incorrect boot order (i.e. VMs on before Active Directory)
  10. Power on Active Directory servers
  11. Reboot AD servers (one at a time) until they come up smoothly, recognize network (as “domain network”), and serve DHCP, DNS, etc
  12. Power on vCenter and VMM servers
  13. Power on DFS and shared file servers
  14. Power on System Center Operations Manager server to begin monitoring
  15. Power on load balancers
  16. Etc…

Back on topic, this post is about DFS-R (Distributed File System Replication), mentioned in Step 13, and only fully understood in this context today. I probably should have known this by now, but there’s a reason why Step 13 isn’t enough to get DFS-R operational. It catches me by surprise every time when someone reports that data is out of sync, and probably every time since, I’ve had to manually re-sync the data before doing an authoritative sync because some data comes from each side. Finally today, I know why and how to fix it.

Microsoft Technology

Speakers: Lee Dilworth, Clive Wenman (VMware)

Understanding the Use Cases and Implementation Options

Prior to SRM 5, relied on array-based replication
– requires same versions of vCenter and SRM but ESX versions can vary
SRM 5 now supports vSphere Replication (in addition to array-based)
– vSphere Replication requires parity of all versions of vSphere

SRM: Site Recovery Manager
SRA: Storage Replication Adapter

SRM 5 UI allows seeing both sites from one interface

vSphere Replication offers a cost-effective choice/alternative to array-based
– does not replace array-based for the foreseeable future

Technology Virtualization