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February, 2013

Backing Up iSCSI LUNs on a Synology NAS

Last week I did a video showing the iSCSI snapshot feature in DSM 4.2 beta.  I had a lot of people ask for more video demos so here we go.  If there is anything you’d like to see or have ideas please let me know!

Like many Synology users, I use my setup to store virtual machines hosted by VMware.  While I used to primarily use NFS I’m now moving toward iSCSI since Synology added VAAI and snapshot support for iSCSI LUNs.  There are several ways to backup a solution like that.  If you’re in a full production environment I’d recommend a good backup application, like Veeam, but often it’s nice just to do a straight copy of data.  Few NAS allow you to replicate or copy an iSCSI LUN…but Synology gives you an easy way to do it either locally or to another Synology.

In the video below we’ll go through the steps to backup an iSCSI LUN and then show your options for restoring data.


4 thoughts on “Backing Up iSCSI LUNs on a Synology NAS”

  1. Hey Jason, can elaborate on why you prefer iSCSI vs NFS?

    Also, is native multipathing with VMware only *really* available with iSCSI?

    1. Couple things… First, I usually prefer NFS from an ease of use standpoint. I like being able to just connect to the NFS datastore and move files around as needed. Handy…but not a strict requirement for most.

      If performance is key I prefer iSCSI both on Synology and most arrays as well. VMware vSphere has several tie-ins that can help offload work to the storage system. Called VAAI. I did a post on that showing how much faster things like VM copies are and how much less network traffic it generates. There aren’t as many VAAI commands with NFS as there are with block storage (iSCSI and FC). Also, the Synology only supports snapshots on iSCSI so that can be a benefit, too.

      As for MPIO/Multipathing. It’s not a limitation of vSphere it’s a limitation of NFS. There is no good way to multi path NFS like there is with iSCSI. The real question you need that kind of throughput? Even in mid-sized VMware environments I find most people over estimate the amount of storage throughput they need. It’s most often about the IOPS..less about the throughput. But if you need more than 1Gb your options with NFS are to manually load balance exports/datastores or go to 10Gb.

  2. I’m coming at it from the angle of resiliency. Let’s say I have 8 NICs per host, I want to eliminate my switch as a single point of failure. I have 4 going to 1 switch, 4 going to another. With NFS, if I have my management, storage, vmotion, and vm networks in separate VLANS, if I lose the switch that has the gateway IP for those VLANS then I’m sunk, correct? Even though I’m connected to another switch, if my management network can’t talk to my storage network via the VLAN gateway IP, it’s as if I’ve lost both switches?

  3. Excellent Video! Can you elaborate on the retention period of iSCSI LUN backups? is it a full backup once, then incremental forever? Can you delete backups after a certain period of time to save on disk space?

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