ZFS RAID1 with HDD of different models

6502

6502

I have 1TB WD Black 2.5" (WD10JPLX). I plan to buy another 1TB WD Black 2.5" for RAID1 (ZFS) but in fact the second disk is HGST (HTS721010A9E630) rebranded to WD and first is the original "black" WD. Probably the performance will not be identical. Is there risk for unstable work of RAID? First is with 32MB cache and the other with 64MB.
 
Usually the slowest disk in a vdev dictates its speed and zfs can throttle accordingly. The difference for those two drives shouldn't be that big to have any noticeable effect; IOPS and read performance will be the added performance of both drives, so the mirror will outperform a single disk stripe anyways..

Also we're talking about HDDs here - so usually performance is not really the focus for HDD-based pools nowadays, but rather storage space per budget. For such small drives however, this doesn't really apply. 1TB SSDs are dirt cheap and have better performance and energy consumption by orders of several magnitudes...
 
I agree with what sko said, there isn't any issues on being composed between multiple brands. On my machine, I rebuilt my raidz1 setup that was 3 hdd's (one that was a 5400 and the others at 7200). Sure I did see some performance because of the slow drive, the setup worked fine without any issues. That setup was swapped with 3 ssd's (3 different brands/models) and again no issues. The one area that I've seen reports of having issues is the vdev pool being a mix of hdd and ssd drives.
 
One thing about mixing brands and maybe even types:
1GB on brand A may not be 1GB on brand B. The way around that is to partition the drives; that way you can guarantee the vdevs are all the same size.
 
I even consider it a good idea to have heterogenous sets of RAID disks. If there is a specific problem with one specific model of harddrive or SSD they would have a chance to fail at the same time (aka during a resync after the first one fails).
 
cracauer@ said:
I even consider it a good idea to have heterogenous sets of RAID disks. If there is a specific problem with one specific model of harddrive or SSD they would have a chance to fail at the same time (aka during a resync after the first one fails).
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I've talked with people that deliberately avoid "same brand same model same batch" if the devices are going to be RAIDed in any manner. Achieving that can often be as tough as finding all same.
 
mer said:
I've talked with people that deliberately avoid "same brand same model same batch" if the devices are going to be RAIDed in any manner. Achieving that can often be as tough as finding all same.
Click to expand...
Our main supplier for server hardware usually asks if we want mixed batches when we order a bunch of identical hard drives/SSDs. If they don't have wholly different batches, they at least try to pick serial numbers that are far apart.
 
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