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You may not be able to grow an existing vdev, but you can add another vdev to an existing zpool. And although having all vdevs be identical gives more consisten
by hhw 9y ago
You may not be able to grow an existing vdev, but you can add another vdev to an existing zpool. And although having all vdevs be identical gives more consistent performance, it’s also possible to mix different vdevs in the same zpool. Multiple vdevs also result in better performance, as each raidz/raidz2/raidz3 vdev only has the equivalent IOPS of a single drive, but without the write hole drawbacks of more traditional RAID5. Recovery time with multiple vdevs would also be much better than a single large vdev, which is becoming more and more of a concern as drive capacities continually increase while IOPS remain more or less the same.
- tjoff 9y agoYes, all very true, but all of that is utterly irrelevant for the home NAS in 95% of cases since performance is not that critical and it comes at an enormous cost of wasted space, also physical space is a huge deal since adding two redundancy drives for each raidz2 quickly adds up. As well as noise etc. And if we want to talk optimized setups it really isn't recommended to add new vdevs to a already populated pool since the usage will be quite unbalanced and affect performance as well.