HAMMER, disk mirroring and secure NFS

Jasse Jansson jasse at yberwaffe.com
Sun Mar 26 04:52:59 PDT 2017

On 2017-03-26 12:14, Michael Neumann wrote:
>> 1) On my main PC I'm planning to install DragonFlyBSD on a small SSD and
>> use two 6TB disks for my home directory: one disk for the master PFS,
>> one as a copy with HAMMER's mirror feature.
>> I have a 7200 rpm Seagate IronWolf and a 5400 rpm Western Digital Red.
>> Can I use them together or HAMMER's mirror feature requires (or work
>> best with) identical disks (or disks from different brands but same
>> speed)? If I can use them do you suggest using the faster disk for the
>> master or the mirror?
> No problem here. You can even mirror over slow internet connections.
> HAMMER is using logical mirroring, i.e. it creates two completely
> separate file systems (with identical logical content), so neither the
> physical block size, nor the speed of the disk matters. Of course you
> have to give the second slower disk enough time to keep track.

A related question:

Can the mirror copy be accessed/mounted as a separate filesystem and if 
so, can every file be read file-by-file or can it only be restored as 
the whole dataset ???

I belive that ZFS mirror-stream (or what it's called) can only be 
restored as the whole shebang but I have never tried it myself.

Long time since I had DF installed on a computer, might mitigate this 
today but I don't have enough HD's to try this mirroring thing by myself 
right now.

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