In this article, I walk through how I added 6TB to my homelab’s storage using a SAS controller, an old power supply, a 3D printed enclosure and some cheap parts from AliExpress for less than AU$200.
Introduction #
My home server consisted of 4 500GB SATA HDDs. Two of them were spare 3.5" drives, and the other two were 2.5" drives pulled from old laptops. I used ZFS to mirror the drives in pairs and then stripe the mirrors, forming a RAID1+0 configuration. It wasn’t long before I started filling up the single terabyte I had, especially with other family members using the same zpool.
My original plan was to purchase a pair of decently large hard drives which I could replace one of my mirrors with, but I was disappointed to realise that they costed hundreds of dollars each. This left me essentially keep hunting for good deals on drives until I would eventually cave and buy them because I needed the extra storage.
That was until I met a very nice person who offered me a whole lot of old SATA HDDs for AU$100. It included a mix of drives from 160GB to 1TB, including more 500GB 2.5" drives than I’d ever need, and more importantly, 11 2TB 3.5" drives.
smartctl indicated one of the drives as completely faulty, and another was reporting errors. This left me with 9 usable 2TB drives.
Components #
At this point, I already knew it was possible to connect more hard drives to a server through a HBA (host bus adapter) in a PCIe slot. However, I only knew about SATA expanders, which was the cheapest and most logical solution I had.
While searching for these cards, it realised that I had to find somewhere to put these drives. My existing case could fit a maximum of 3 3.5" drives and another 2.5" drive. Buying a new case with enough capacity would be too expensive to justify, so I researched how I could DIY an external enclosure.
I found Sloth Tech TV’s 6x 3.5" Hard drive enclosure, which is printable on a regular sized 3D printer like a Creality Ender 3. I was able to get this printed by a seller on Facebook Marketplace for AU$30, which is probably more expensive than buying a spool of filament and borrowing a printer at a makerspace, but oh well. The enclosure is stackable and can hold 2 120mm fans for extra airflow.
Sloth Tech TV’s video on Cheap HBA and SAS expander options helped me tremendously in discovering SAS HBAs and multi-lane internal mini-SAS connectors.
I chose to purchase a LSI 92xx-8i card which was pre-flashed to 9211-8i IT mode on eBay for AU$40. The listing included 2 SAS SFF-8087 breakout cables which each split their four lanes into SATA connections, which can be purchased on AliExpress for about AU$6 each.
I concluded from my research that SAS HBA cards typically feature SFF-8087 ports internally, and some cards also feature additional SFF-8088 ports. SFF-8088 cables are more durable and look very nice, but both SFF-8088 to SFF-8088 cables and SFF-8088 to SATA cables are considerably more expensive than SFF-8087 to SATA cables.
You could buy SFF-8088 cables and SFF-8087 cables, and attach an adapter to your enclosure (Sloth Tech TV also has a 3D-printable case for these). This gives you more flexibility in regards to how far away you can put your enclosure from your server.
By using this setup, I can connect 6 external 2TB drives, giving me an extra 6TB of storage in the same mirror + stripe configuration. I also have 3 leftover drives which I can use to replace failed drives.
Power #
To power the external drives, I decided to harvest a power supply from an old PC, which very simply included a 24-pin motherboard connector, a 4-pin CPU connector and 2 SATA connectors. I bought 2 1-to-3-connector splitters from AliExpress for AU$3 each to power my 3 drives.
I also bought a jumper bridge for the 24-pin motherboard connector for AU$1. This is necessary because the power supply will not turn on unless pins 4 and 5 are jumped. This could also be done with a paperclip or a short piece of wire.
Because these pins are always jumped, the external drives will always be on regardless of the main server. To fix this, you could use a dual PSU adapter to link their power states.
Migrating Data #
I was greeted by a nice BIOS screen listing my hard drives and their sizes, confirming that they were all recognised by the HBA and that the card was in IT mode.
I zpool added the drives in pairs, and then zpool removed the old ones to free up 2 slots inside of the main case. Perhaps those slots will later be used for SATA SSDs.
zpool status output during evacuation of data from pool
Conclusion & Alternatives #
This project was great fun. It taught me a lot about SAS hardware which I would never know about if I chose to just buy 2 new SATA drives.
If you already have a 3D printer and want to hold 6 3.5" drives (which are hotswappable), 3 2.5" drives and the rest of your hardware inside a single 3D printable case, I’d highly recommend printing assembling makerunit’s 3D Printed 6-Bay NAS case. To say it’s beautiful would be an understatement, and if I didn’t already have a case I would definitely spend the time and effort to build this instead. Just look at the magnetic covers!!