Using iSCSI to store your Apple Photos library on a Synology NAS

You got yourself an Apple computer, but it does not have enough space to store all your photos? You happen to have a Synology NAS and want to know how to use it to store your photos? I will show you how with iSCSI!

Apple recommends having your Photos library stored on a hard drive hat has been formatted to the HFS+ file system. That means using the standard SMB or AFS file sharing protocol Synology provides is not the way to go. But Synology does provide iSCSI support, which allows your computer to think that a hard drive located in another computer on your network is actually physically attached to your computer. That way we can then format it to HFS+ and use it as a Photos storage location.

Setting up iSCSI on Synology

The first thing we will do is create an iSCSI LUN (Logical Unit Number) which we use in order to map a "virtual" volume to a physical disk. You can create one by opening up the Storage Manager, heading over to iSCSI LUN and pressing the Create button to start the wizard.

Block-level LUN is recommended as it is much faster than a regular LUN. Unfortunately, for that setup you will need to dedicate an entire disk and cannot use an existing volume like a regular LUN can. Although block-level says it will be on RAID, it can be done on a single disk with no data protection.

 As a reference, for a regular (not block-level) LUN setup I get speeds typical of USB 2.0. I got an average of 15MB/s write and 20MB/s read speeds compared to 60MB/s with SMB.

After creating the LUN, the iSCSI Target should of automatically been made to point to the LUN created. If it did not, run the wizard with the Create button. Also make sure that the Target is properly mapped to the LUN created earlier.

This is all we needed to do on the NAS. We will now configure OS X.

Setting up OS X with an iSCSI initiator

Unlike other operating systems, Apple does not include an initiator free with OS X which is required in order to mount the iSCSI volume we created. The cheapest iSCSI intiator I found was DAEMON Tools for Mac 4 which costs $20 and requires an additional $50 for the iSCSI Initiator license which brings the setup total to $70. There is a 20-day trial you can use to determine if an iSCSI setup is right for you; I suggest you try it first with this guide.

One installed and launched, you will see the iSCSI tab. Within there, it should have automatically discovered the iSCSI Target on your Synology. You can press the Play button or right-click on the target and select Connect.

Use Disk Utility in order to format the iSCSI disk to HFS+. The volume should then automatically be mounted and used just like any other storage connected to your computer.

With a block-leven LUN, I get the same speeds as I would accessing it like a normal network share. I average around 60MB/s read and 50MB/s write.

Hopefully these steps worked and now you are able to use your Synology NAS in order to store your Apple Photos library! The $70 entry for an iSCSI Initiator is a bit high, but being able to access your photos without being tethered to a hard drive is fantastic. Another alternative is to use an Apple Airport Extreme.