Improving ext4: bigalloc, inline data, and metadata checksums

Posted Dec 9, 2011 0:57 UTC (Fri) by tytso (subscriber, #9993)
In reply to: Improving ext4: bigalloc, inline data, and metadata checksums by nix
Parent article: Improving ext4: bigalloc, inline data, and metadata checksums

What I have under my desk at work (and I'm quite happy with it) is the Dell T3500 Precision Workstation, which supports up to 24GB of ECC or non-ECC memory. It's not a mini-ATX desktop, but it's definitely not a server, either.

I really like how quickly I can build kernels on this machine. :-)

I'll grant it's not "cheap" in absolute terms, but I've always believed that skimping on a craftsman's tools is false economy.

Improving ext4: bigalloc, inline data, and metadata checksums

Posted Dec 9, 2011 7:41 UTC (Fri) by quotemstr (subscriber, #45331) [Link]

> Dell T3500 Precision Workstation, which supports up to 24GB of ECC or non-ECC memory.

I have the same machine. Oddly enough, it only supports 12GB of non-ECC memory, at least according to Dell's manual. How does that happen?

(Also, Intel's processor datasheet claims that several hundred gigabytes of either ECC or non-ECC memory should be supported using the integrated memory controller. I wonder why Dell's system supports less.)

Improving ext4: bigalloc, inline data, and metadata checksums

Posted Dec 9, 2011 12:40 UTC (Fri) by nix (subscriber, #2304) [Link]

Oh, agreed. I've seen multiple rounds of friends deciding to save money on a cheap PC, trying to do real work on it, and finding the result a crashy erratic data-corrupting horror that is almost impossible to debug unless you have a second identical machine to swap parts out of... and losing years of working time to these unreliable nightmares. I pay a bit more (well, OK, quite a lot more) and those problems simply don't happen. I don't think this is ECCRAM, though: I think it's simply a matter of tested components with a decent safety margin rather than bargain-basement junk.

EDAC support for my Nehalem systems landed in mainline a couple of years ago but I'll admit to never having looked into how to get it to tell me what errors may have been corrected, so I have no idea how frequent they might be.

(And if it didn't mean dealing with Dell I might consider one of those machines myself...)