Using FC San as DAS for Truenas

Hello, I’m trying to use some old hardware that I have. I have an Fibre Channel array that has about 300TB of space. The maximum LUN size of the array is 64TB, so I can make like 5 max size luns. I would like to frontend this array with a Truenas server. I do not want Truenas to be an FC target, I only want the FC to act as DAS. The FC Array will be directly attached to the server using HBAs and native FC. The fibre channel san is very well equipped to deal with failing drives and bit rot, so I do not need Truenas to deal with that at all. I would only be using Truenas to aggregate the luns (via a pool) and provide a nice manageable interface and filesharing features. The Truenas server would be serving NFS and SMB.

I would create multiple vdevs each with a single 64tb lun and add them to a pool, with no raid at all. The raid will be done at the FC array level. Is this asking for trouble? Does this work? Is there a better way to do this?

Welcome to TrueNAS forums.

First, using hardware RAID, (aka “maximum LUN size…”), is not supported. TrueNAS’ use of ZFS IS the RAID solution. Using multiple layers of RAID makes no sense.

Next, TrueNAS, both Core & SCALE, are appliance like firmware, not general purpose OSes. Thus, they don’t support things like Fibre Channel host bus adapters.

TrueNAS and ZFS are not the end all to NAS, (home, small office or Enterprise). Their are lots of situations where either or both just don’t fit. This is one of them.

I am not trying to stop you, but, you are loosing out in some of the benefits of ZFS by using hardware RAID. For example, a ZFS scrub is somewhat useless. If it finds corruption in data, ZFS can only tell you which file(s) are corrupt. Not automatically fix them.

Further, COW, (Copy On Write), protections against pool corruption are lost with any caching storage, like hardware RAID. Thus, on crash or power loss, you could end up loosing a few seconds of data. Or, in the more rare case, the entire pool.


It would not be expected to work.
The HDDs could be reused in a SAS JBOD enclosure.