ZFS on iSCSI devices (with Encryption?) [closed]

Question

I own an old NAS (Buffalo TeraStation Pro II) with four 500GB Samsung HD502IJ SATA drives. On the NAS i installed Debian 9.

The NAS is pretty old and consumes a lot of engergy already without any HDDs connected to it. Therefore i plan to use it just as a Server for storing Backups, which will be disconnected from power most of the time (to keep backups save). This is a home setup and it's about using spare hardware for additional data safety. Therefore i'm not planning to put a lot of money into it (i can't solder in ECC ram in the old NAS anyways...).

As the NAS is pretty limited on computing power and memory (ARM; Marvell Orion ; 128MB RAM)[http://buffalo.nas-central.org/wiki/Category:TerastationProV2 ], i can't run ZFS on it directly but i still want to use ZFS's snapshot capabilities for my Backups. I would like to use encryption of the disks but it's not the most important thing as the device is secured at home and the data is more like family photos, nothing critical somebody will try to steal on purpose.

My current plan would be:

• NAS: 3 partitions on each disk: SWAP (~512MB), RAID1 with Debian(~10GB), Rest is shared over iSCSI.

• PC running the backups: connecting to the 4 iSCSI targets, decrypting them with veracrypt and mounting them as ZFS Pool (RAID Z1) to store the backups.

The parameters i plan to use:

• GZIP-9 compression as speed isn't important (http://nex7.blogspot.com/2013/03/readme1st.html recommends otherwise when it's about speed but it also says if i'm going to use GZIP the speed of level 9 isn't much slower than GZIP-1 and compression is better)

• ashift=12 (for correct alignment; hope that is still true if the device is a veracrypt...?)

My Questions:

1. It's always said that ZFS should see the disks as direct as possible, so it can optimize. Is iSCSI - or more importantly: veracrypt - hiding any important disk-parameters from ZFS?

2. For working with iSCSI and ZFS, would you recommend to use LUKS instead of veracrypt?

3. What would you think about doing encryption on the NAS itself (before iSCSI sharing) instead of on the client PC?

4. When seeing the configuration (and hardware), do you have any other recommendations about additional parameters?

Answer 1

None of this is a good idea for ZFS.

The slow CPU, limited RAM and desire for encryption and heavy compression will make this a very ineffective system. I would not pursue ZFS on this server.