Tag Archives: disaster recovery

ZFS Replication and Recovery with FreeNAS

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We get requests to recover data from a secondary platform all the time. RPO (recovery point objective) of 30 minutes can be challenging to small to medium sized companies, especially if there is an SLA (service level agreement) to meet.

This week, my team and I took some time to create a FreeNAS replication demo for a potential client. I thought I document the whole thing about ZFS replication, the key steps to set it up and show how recovery is done.

ZFS Snapshots

ZFS replication relies on periodic ZFS snapshots. ZFS snapshot is an inherent feature from the ZFS file system, and often used as a point-in-time copy of the existing ZFS file system tree in memory. Once a snapshot has been triggered, either manually or on schedule (periodic), the file system tree and its metadata in the memory are committed to disk to ensure an updated and consistent state of the file system at all times.

To start, a running snapshot policy on a schedule must be in place. This snapshot policy can be on a specific dataset or zvol, or even the entire zpool. Yeah, I am using quite a few ZFS terminology here – zpool, zvol, dataset. You can read more about each of the structures and more here.

Once the ZFS replication task has been setup, every snapshot occurred in the snapshot policy is automatically duplicated and copied to the target ZFS dataset. Usually, the target ZFS dataset is on a secondary FreeNAS storage server, serving as a disaster recovery platform. Sending and receiving data in the snapshots rely on SSH service.

This is the network diagram explaining the FreeNAS ZFS replication setup.

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Disaster Recovery has changed

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Simple and affordable Disaster Recovery? Sounds oxymoronic, right?

I have thronged the small medium businesses (SMBs) space in the past few months. I have seen many SMBs resort to the cheapest form they can get their hands on. It could be a Synology here or a QNAP there, and that’s their backup plan. That’s their DR plan. When disaster strikes, they just shrug their shoulders and accept their fate. It could be a human error, accidental data deletion, virus infection, data corruption and recently, RANSOMware! But these SMBs do not have the IT resources to deal with the challenges these “disasters” bring.

Recently I attended a Business Continuity Institute forum organized by the Malaysian Chapter. Several vendors and practitioners spoke about the organization’s preparedness and readiness for DR. And I would like to stress the words “preparedness” and “readiness”. In the infrastructure world, we often put redundancy into the DR planning, and this means additional cost. SMBs cannot afford this redundancy. Furthermore, larger organizations have BC and DR coordinators who are dedicated for the purpose of BC and DR. SMBs probably has a person who double up an the IT administrator.

However, for IT folks, virtualization and cloud technologies are beginning to germinate a new generation of DR solutions. DR solutions which are able to address the simplicity of replication and backup, and at the same time affordable. Many are beginning to offer DR-as-a-Service and indeed, DR-as-a-Service has become a Gartner Magic Quadrant category. Here’s a look at the 2016 Gartner Magic Quadrant for DR-as-a-Service.

gartner-mq-dr-as-a-service-2016

And during these few months, I have encountered 3 vendors in this space. They are sitting in the Visionaries quadrant. One came to town and started smashing laptops to jazz up their show (I am not going to name that vendor). Another kept sending me weird emails, sounding kind of sleazy like “Got time for a quick call?”

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