The original post: /r/datahoarder by /u/deathpulse42 on 2024-12-26 18:05:26.
Context/Set-up:
HP Proliant DL380p Gen 8
HP P822 Smart Array Controller [in HBA/IT/passthrough mode]
Ubuntu 18.04 LTS [bare metal]
ZFS RAIDz2 [0.7.5-1ubuntu16.12] -- currently all 512e/SATA-3 drives
HP D2600 LFF Disk Enclosure [SAS-2 - 6Gbps | SATA-2 - 3Gbps]
TL;DR: Can I use 4kn SAS-3 drives in an 8th gen HP Proliant server running Ubuntu 18.04 LTS with an 8th gen HP RAID card in passthrough mode?
Considering a large storage upgrade to my current set-up. I have a D2600 disk enclosure with all SATA-3/512e drives1, and that's been working great for the last 4 years. No issues.
Another D2600 is on its way -- all that I need to decide on is the drives for a new ZFS array.
I've been doing some spreadsheet work with ebay prices, $/TB, and the like, and after some "best value vs. riskiness" number crunching, many of the best value candidates are refurbished/recertified enterprise [SAS-3 - 12Gbps]2 4kn drives (probably due to lower demand vs 512n/e in the used market because of [1] the SAS interface and [2] the exact uncertainty with legacy storage controller compatibility that I'm concerned about lol).
I have scoured many internet forums over the past week or so, and from what I can tell, HP didn't ever officially support 4kn on their 8th gen RAID cards. No problem, I figured -- I have mine in HBA/IT/passthrough mode for use with ZFS, so no hardware RAID support required! But I saw this post by TechMikeNY that states "4Kn drives – SAS only – could work in these [8th gen or earlier] servers in a non-RAID/pass-through configuration [exactly what I have]. Though the OS running on the server would need to support 4Kn formatted drives as well. Due to the variables involved, we do not recommend it."
I haven't been able to find any stories/posts where someone has successfully used 4kn SAS drives with 8th gen HP RAID cards in HBA mode with Ubuntu 18.04 LTS. From what I've read about and have understood regarding the whole 512n/512e/4kn discussion, I think these 4kn SAS drives could work, especially since all of my HDDs show up as "512 bytes logical, 4096 bytes physical" anyway. **Also, the OpenZFS documentation describes a process by which one can use ZFS in Ubuntu 18.04 "on a drive which presents 4 KiB logical sectors (a '4Kn' drive)" as a the root filesystem, so I figure the OS support is probably there?
I wonder if anyone has any advice on the feasibility of this combination of parts. I don't necessarily need the SAS benefits, but if I can get them for a small premium (or even less in these cases), I figured I might as well get 2x speeds (albeit at SAS-2) and be able to do a more reliable dual-domain cabling configuration. If not, I can just go with the tried-and-true SATA-3 drives.
TBH, part of me just wants to buy 2-3 cheaper low-capacity 4kn SAS drives and just see if it works as a proof of concept...
Thanks for any help or advice you can provide. :)
Specifically, this is the model number I'd buy if I can prove that the 4kn SAS drives would work:
WD WUH721414AL4200 14TB SAS 12GBPS 4KN 3.5IN HC530 HDD
1 Yes, I realize I can only achieve [SATA-2 - 3 Gbps - 300 MB/s] speeds with this set-up, but it works perfectly fine for my use case -- a Plex server just doing sequential reads and writes of large media files for the most part.
2 Yes, I also realize I would be getting only SAS-2 speeds from these SAS-3 drives, but that's perfectly okay with me, especially since I can't find any older SAS-2 drives with the higher capacities that I'm aiming for. Plus, they are all much older drives in general, and I'd worry about reliability.