eSATA on Macs

Geek post warning: feel free to skip this, folks, it’s intended mostly for Google.

As of April 2009, eSATA for Macs is a bit flaky. Well, it probably doesn’t have to be, but cheap eSATA is flaky. Specifically, products based on the Silicon Image 3132 chipset cause random but repeatable kernel panics on Mac OS X systems. Here’s what I know so far:

Until recently, I’ve been editing off a bunch of 1Tb Firewire 800 hard drives. They’re Lacie RAID 0 units, and they work well enough. 65Mb/sec read or write is enough for the sort of editing I’m doing (ProRes 422). They’re a bit big and heavy to be truly portable, but it’s reasonably easy to bung one in a bag with my MacBook Pro and edit HD footage away from base.

However, they’ve a reputation for being unreliable, and indeed one of mine is starting to get a bit flaky. They’re also full, or at least ‘more full than I’d like.’ So a few months ago I started looking for alternatives.

I could have pushed old stuff into a Drobo, but they’re very slow indeed. Not just ‘too slow to edit off,’ but ‘too slow to move a typical 250Gb project onto.’ An hour’s archiving activity is fine, but a day is ‘deep backing store’ territory. I might explore the new DroboPro, but the proprietary nature of the filesystem concerns me. Hardware RAID 5 and swapping out entire disk sets may be more cost-effective.

FireWIre 800 is pricy, in part because it’s hard (in the UK) to source bare enclosures and fill them with one’s own disks, which is what I used to do with FireWire 400. It’s also not that quick, in the grand scheme.

No, the future is eSATA, the external version of the connector that hooks up our (internal) hard drives these days. Quick, cheap, reliable. Well, pick any two. Or maybe one. Read on:

A couple of months ago I bought a Sonnet eSATA expresscard for my MacBook Pro. They sell two, and I bought the cheaper of the options. I also bought a remarkably cheap trayless eSATA drive enclosure, an Edge10 DAS401. For the money it’s really not bad. I’m unimpressed by the shielding around the (internal) power supply, and it could be a little quieter, but it’s a solid enough box and easy enough to use. Thumbscrews everywhere are a nice touch. Cheap, but cheerful, and it has a port replicator so all four drives hang off a single eSATA cable.

The card and the enclosure talk to each other absolutely fine. Software RAID is out of the question: I managed to brick a pair of drives by trying it, having to reformat them via Windows before I could connect them to OS X again without triggering a kernel panic. But a single drive (Hitachi 1Tb units) pushes about 95Mb/sec read/write, which is ample for my purposes. The same drive mounted internally in a Mac Pro pushes 105Mb/sec, so the external overhead is acceptable.

It’s also trivial to pull a drive from the enclosure and shove it on a shelf, in a WiebeTech Drivebox. This appears to be my new equivalent of ‘putting the miniDV tapes in a shoebox.’

There are, however, some problems. Specifically, the eSATA card drivers are flaky. They mostly work, but mounting or unmounting a drive, or connecting or stopping the card, can cause kernel panics. Boff! Gone. Game over. Once it’s all running it works just fine, but hot-swapping is a no-no. In fact, the best approach is to shut everything down, configure the system, then power it all up. Which is fine, if mildly inconvenient.

However, since I bought the Expresscard Sonnet have posted a dire warning on their site:

“Temporarily not recommended for Mac systems with greater than 2Gb of memory.”

Yikes. My MacBook Pro has 4Gb.

The problem, I believe, is the chipset, which is based on the Silicon Image 3132 product. Most cheap eSATA systems seem to use this design, and the drivers, whether your card is from Sonnet or Lacie or anyone else, come directly from Silicon Image. And they stink. Luckily, for me, they seem to work OK. Ish.

At least, they do in the MacBook Pro. I recently bought an end-of-line 2008-model Mac Pro, and that’s a whole different animal.

The Edge10 box came with a bundled PCIe eSATA card, a tiny little thing with a dashing red board and a chip inscribed ‘Silicon Image 3132.’ Oh, crap. Sonnet’s equivalent card looks identical to the one I have, and also carries the dire warning about Mac systems with more than 2Gb RAM; my Mac Pro has 10Gb.

Sure enough, the Mac Pro throws a kernel panic at the merest hint of hooking up drives in the Edge10. It does, occasionally, work. Sometimes it’ll push data solidly for 20 minutes or more, but usually – and certainly ‘eventually’ – it panics. Hard lock. Reboot. Bastard.

Frustratingly, the way out of this appears to be to invest in a Sonnet Tempo E4P card, which is another £250 but uses some chipset that doesn’t involve the dreaded Sil3132.

Alternatively, Silicon Image might update their drivers. They haven’t touched them in almost two years, but you never know.

Until they’re fixed, however, the only sure approach is to stay away from Sil3132-based setups with Macs. They either don’t work at all, or aren’t reliable.


  1. Thanks for this. It explains why I keep losing connections to my esata hard drives on my Mac Book Pro. Did you ever find a non 3132 express 34 to esata card?

  2. I think the only non-3132-based ExpressCard is the Sonnet Tempo SATA Pro card, which is about two or three times the price of all the others. It’s clearly doing something different, though, in that it’s the only card that can cope with RAID bandwidths – the non-Pro, 3132-based cards max out more-or-less at single-drive data rates.
    On the desktop, I’m now using one of the RocketRAID cards. The setup is a little odd, but it seems to be entirely stable with 10.5.8.

  3. Replying to my own post: Silicon Image 3132 drivers up to and including the current release as of writing (1.5.16, dated August 2007), are quarantined by the Snow Leopard installer. While this might shake Silicon Image into action, my guess is that Sil3132-based eSATA adaptors are now basically junk on Macs. They were before, but now more so.

  4. In a bit of a shocking development, Silicon Image have released a 1.1.11 base (non-RAID) beta driver, specifically for OS X 10.6/10.6.1. I haven’t tried it yet, but the link to the driver download page above lists it. Use with caution, but it looks like Sil3132-based cards aren’t dead to Macs yet…

  5. I’m currently using them.
    spent the whole evening doing so.
    it’s the nightmare of 10.5.X once more.
    I havent had a working esata card in a year and a half.
    1.1.11 is exhibiting the same faulty behavior as the previous garbage drivers.
    SI need to get off their collective asses and repair this.
    how hard is it to make a fucking 10MB driver that works.

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