Don’t go down the road of breaking the ZFS array to “rotate” disks offsite. As you’ve seen, the rebuild time is high and the resilvering process will read/verify the used size of the dataset. If you have the ability, snapshots and sending data to a remote system is a clean, non-intrusive approach. I suppose you … Read more
As I suspected, it’s based in the VSS subsystem (source) which also explains it’s async nature. The de-dupe chunks are stored in \System Volume Information\Dedup\ChunkStore\*, with settings in \System Volume Information\Dedup\Settings\*. This has significant impacts to how your backup software interacts with such volumes, which is explained in the linked article (in brief: w/o dedupe … Read more
With ZFS, it’s 1 GB per TB of actual disk (since you lose some to parity). See this post about how ZFS works for details. For example, if you have 16 TB in physical disks, you need 16 GB of RAM. Depending on usage requirements, you need 8 GB minimum for ZFS. UFS requires much … Read more
“copies=2” (or 3) is more designed to be used with pools with no redundancy (single disk or stripes). The goal is to be able to recover minor disk corruption, not a whole device failure. In the latter case, the pool is unmountable so no ditto blocks restoration can occur. If you have redundancy (mirroring/raidz/raidz2/raidz3), the … Read more
Snapshots are read-only. If you need those folders gone then you have to delete the whole snapshot. You can make a backup (with something like tar), excluding the offending folders, then delete the snapshot. Obviously the backup is now in tar, or whatever, format; but at least you still have a backup copy.
To change the properties (be it compresson, deduplication or checksumming) of already written data, the zfs approach is to run the data through a zfs send | zfs receive sequence. Obviously, you do not need to offline the system for that, but you will need enough resources in your zpool / on the system to … Read more
Not yet. Work’s in progress ZFS Crypto support · Issue #494 · zfsonlinux/zfs · GitHub (2011-12-14) ZFS Encryption by tcaputi · Pull Request #4329 · zfsonlinux/zfs (2016-02-11) – 593 parts to the conversation, “… too big for github to handle effectively … moving it to a new PR …” ZFS Encryption by tcaputi · Pull Request #5769 … Read more
zpool status -v should tell you which disk is online or not.
If you have a descendent ZFS filesystem, for example tank/newfs. Then you will not find files in tank/newfs in the /tank/.zfs/mysnapshot folder, only the mountpoint newfs will exist. If you want to access the files you need to look for your files in the /tank/newfs/.zfs/mysnapshot folder.
You would need to rewrite your data to the expanded zpool in order to rebalance it. Otherwise, as time passes, your writes will be distributed across the entire pool.