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Disk Upgrades

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Jul 10, 2019
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#1
Hey all,

so I am looking to build my first FreeNAS build and wanted to clarify something about ZFS and how to expand later on down the road. I currently am looking at a 6 drive array with 8tb disks. However, I cannot afford the 8 tb disks right now. I plan on running RAIDZ 2.

Would it be better to build a 6 drive with 1 or 2 tb drives to get started and then later when I can afford the 8 tb drives, replace them 1 by 1 until all 6 drives are 8tb?

The plan being that since a vdev is created with a specific amount of disks and can't be expanded afterwards with out striping across multiple vdevs losing a layer of drive safety, does creating a lower capacity pool first populating all my slots first and then upgrading drives later seem worth it? Or is there a better upgrade path that I don't know about?

Also, what do you all think of WD Gold "enterprise" drives? Are they any better or worse than WD Red drives for this application?

I found these threads, but it didn't quite give me the answer I was looking for. Thanks in advance! Any help?
https://www.ixsystems.com/community...ion-after-expanding-volume.42871/#post-279801
https://www.ixsystems.com/community/threads/advice-on-adding-drives-expanding-a-pool.71521/
 
Joined
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#2
You are correct that would be the upgrade path. It would cost more money in the long run to do the upgrade scenario because you are buying 12 disks. Adding a new vdev would be a better option if you're case supported that many disks.

Stick with wd reds, they are cheaper, use less power, have less heat. Golds have a longer warranty and will be a like faster (7200rpm).
 

Constantin

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#3
The VDEV cannot be expanded but you can always add another (similarly configured) VDEV to an existing pool. The drives that make up each VDEV don't have to be the same size either. For example, yesterday we had a thread in the "Will it FreeNAS?" section where someone was seeking a inexpensive system with up to 50TB of usable capacity.

One option discussed there (to stay in budget) was to buy inexpensive used, but NAS-grade HGST drives (3TB each, 3-year warranty, USD60/ea) and create an initial 9TB VDEV using a 6-drive, Z2 configuration. VDEVs added later to the pool would have to feature higher-capacity disks to enable 50TB of capacity since the server chassis I recommended can handle 24 drives.

SuperMicro offers a chassis (the 826) that can hold up to 12 drives, has redundant power supplies, etc. and can be very inexpensive used on ebay. So you could start off with that chassis and 6 drives, then add another 6-drive VDEV as capacity needs and funding require/allow (though be aware that this is a 2U server re: PCIe expansion slots and CPU HX heights). Or go for the CSE-836 and be able to handle 16 drives and full-sized PCIe cards. The upside of a 2-VDEV pool is higher IOPS, the downside is higher initial cost (usually) along with higher power consumption.

So, it might make sense to start with inexpensive drives and plan to replace them one by one later while allowing the resilver to complete each time. That allows you to minimize power consumption (only one vdev) and perhaps you can repurpose the old drives as off-site backups for important data. Overall, the cost may turn out to be a wash, depending on the trajectory of HDD prices.
 
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Joined
Jul 10, 2019
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#4
Awesome, thanks guys. those hgst drives seem like a good deal to start out with. in RAIDz2 it would probably net me 7-8tb usable or so.

Another thought that I had, is that if I start with this lower cost build and decide later on to expand, I could do a whole separate system and just copy data over to new system. Keep the old system as an offsite backup to my family's NAS with all their pictures.

I just really wanted to make sure the drive replacement was an option to increase storage capacity.
 
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