Is there something that lets you connect a LSI2308 to more than 8 SATA drives and lets you hot swap drives? If so, what do I need to search for on google?
(Background: I have a LSI2308 PCI card which is attached to 8x SATA hard drives (2x 4 drive RaidZ2) and I am looking to attach a couple of spares or a mirror SLOG)
A SAS expander would let you do that.
(SATA port multipliers A) work badly and B) don’t work with LSI HBAs, period, based on the experience of a friend who bought some once.)
A note for those unfamiliar with SAS expanders: yes, they allow you to connect more drives… but connecting more drives via SAS expander will not typically improve performance, and may even degrade it somewhat.
That’s because a SAS expander just lets you connect more drives–it doesn’t give you any more controller bandwidth (or even per-port bandwidth) along with them. Basically, it’s the same reason using a power strip to plug more devices into an outlet won’t get more than 15A out of a 15A circuit.
But if you are just looking to go to ~12 drives, an expander will be perfectly fine here.
Hot swap ability also depends on how the drive is actually connected, so the enclosure/backplane itself.
Don’t forget about the SATA ports on the motherboard. Some motherboards support hot swap (still assuming a hot swap friendly enclosure/backplane).
IME, the majority of mobo SATA chipsets support hotswapping–although annoyingly, they frequently have the ability disabled by default in BIOS/UEFI, where it must first be enabled.
SATA 2, I believe, started hard requiring that be supported, though SATA 1 you could sometimes do it.