Migration from SSD to HDD

[Herr_Merlin]

Hi all,

anything I need to take special care for this task?

I've a System with 8x 2TB Samsung 840 Pro SSDs running as Z1 pool. This is mainly used for data storage. IO wasted.
I would like to replace all those Samsung EVOs with 4 TB SAS 7.2k HDDs.

There are two options:

1. The easy way: replace disk by disk
2. Migrate data and create a new pool

If I go with option 1, could this lead to issues due to the different speeds of the disks?
If I go with option 2 I could do even more fancy stuff, like use 5x6TB disk and keep 3x 2TB Samsung 840 SSDs for meta data in a 3 way mirror..
Or I could by two more 10TB SAS 7.2k disk and go with just 4x10TB disk in mirrors with 2x 2TB Samsung 840 for meta data and add two STEC ZeusRAM for SLOG..
Or go with more disk as it would mean more storage and add 2x RMS-200 for slog.. because.. well I can I assume?

Pool is used for SMB share for Plex and as datastore for nextcloud (about 3TB with lots of small files).
No VMS on that pool. For those I've got a pool out of 6x 1TB NVMe in 3 mirrors.

 

[sretalla]

If I go with option 1, could this lead to issues due to the different speeds of the disks?

Not really, but maybe with ashift, depending on the SSDs native block size.

If I go with option 2 I could do even more fancy stuff, like use 5x6TB disk and keep 3x 2TB Samsung 840 SSDs for meta data in a 3 way mirror..

Correct, this would give you the chance to change the pool layout as well as disk type. (and will be significantly quicker).

 

[Etorix]

Replicating to a whole new pool is the easiest option. But I fail to see the need for any SLOG, much less mirrored RMS-200, in your use case. Except for fun, "because you can" of course.

 

[Herr_Merlin]

But I fail to see the need for any SLOG, much less mirrored RMS-200, in your use case. Except for fun, "because you can" of course.

Well because I've them laying on the shelf... that would be the only reason..

Replication to a new pool won't be so easy. As I would first need to get the data of system to another and later back..