Have a bit of a weird question i haven’t really seen any search results of people running this setup. I use iSCSI blocks to make sure of backblaze personal backup and i know the usual recommendation for an iSCSI block is to use mirrors. but in my case where it’s just going to be plex media storage for 1-2 clients, should RAIDz be fine for this? wanted to get people’s opinion on this.
In either recommendation, i don’t think plex performance demand is very high especially since i only have a max of 2 clients, please correct me if i’m wrong. So in my case, would it still be relatively safe to cap storage at 80%? Or should i go a little lower? I believe mirror iSCSI blocks want to be capped around 40% for maximum performance, i’m not sure if that transfers over to both RAIDz and my use case of a sitting Plex library
iSCSI may write in small blocks, which causes poor disk usage in RAID-Zx. Using Mirror vDevs works better because an iSCSI block can fit on a single Mirror vDev, (then another write could use a different Mirror vDev in the same pool).
It is unclear if you are using an iSCSI volume for actual media files. But if so, why? The media files work perfectly fine on a RAID-Zx pool.
i’m not endorsing anyone to do this, but this is mostly so i can skirt around backblaze personal’s policy. I attach it to a W10 box that runs Plex media server and because it shows up as an actual drive, i can back it up to backblaze at the standard ~$8/month if i pay for the 2 year plan vs paying $60/month for B2
Ah, I understand now. A SMB share would probably not meet that need.
However, my point about iSCSI is that small writes might end up wasting 50% of your space. With a 6 disk RAID-Z1 a small write could be 1 disk of data and 1 disk of parity. Worse for RAID-Z2, with only 33% available for data, (1 disk of data, AND 2 disks of parity). Thus, Mirrors are both storage efficient, and faster.
Now I am not saying that I know how MS-Windows 10 will write an iSCSI LUN on TrueNAS. Perhaps it will do quite well. However, the whole point of iSCSI is to simulate a storage array’s LUN. Hopefulyl someone else with more experience with iSCSI and MS-Windows 10 will be able to answer the question better.
Last, about the iSCSI being best at 50% or less pool occupancy, if the data is mostly read only without much churn, (deletes and new writes like a rotating through T.V. series…), you may get away with higher usage of the pool.
Further, ZFS’ suggested maximum occupancy for any pool of 80% really applies to pools with active churn, deletes and new writes. For a static dataset, like media, you might be able to go higher with the caveat that the newest written media might be more fragmented. And thus, slower reads, which for 2 Plex clients might be okay.
This should be the case for me. With my new setup i plan to have anything unsorted in my main computer then robocopy them over so it should be fairly sequential unless i’m very mistaken about how that works lol. Thank you for your insight! It is much appreciated
