The Lies Disks and Their Drivers Tell 192
davecb writes "Pity the poor filesystem designer: they just want to know when their data is safe, but the disks and drivers try so hard to make I/O 'easy' that it ends up being stupidly hard. Marshall Kirk McKusick writes about the difficulties in making the systems work nicely together: 'In the real world, many of the drives targeted to the desktop market do not implement the NCQ specification. To ensure reliability, the system must either disable the write cache on the disk or issue a cache-flush request after every metadata update, log update (for journaling file systems), or fsync system call. Both of these techniques lead to noticeable performance degradation, so they are often disabled, putting file systems at risk if the power fails. Systems for which both speed and reliability are important should not use ATA disks. Rather, they should use drives that implement Fibre Channel, SCSI, or SATA with support for NCQ.'"
2 out of 3 (Score:4, Insightful)
Cheap, fast and reliable.
Pick any two.
Sorry, what? (Score:4, Insightful)
We're talking about ATA drives?
As in non-SATA drives?
Who has those anymore?
While the article is good for publication in an academic journal like ACM, it's useless for the real world.
For that, the author should tell us whether most drives on the market have NCQ already or not. Popular drives like WD Green and Seagate's various lines.
Otherwise, saying "$A is useless without $Y" is pointless.
Re:almost clicked the link... (Score:5, Insightful)
And yet fails to name any. Looking at Seagates site about NCQ pretty much every consumer model since 2004 has NCQ. This seems overblown.
Re:almost clicked the link... (Score:3, Insightful)
As weighty of an argument as your bet might seem to you, I'd refer actual evidence.
Get Hardware RAID (Score:5, Insightful)
The people who make hardware RAID know all about the lying drives, they get good information from the manufacturer on how to make the drives play nice with the RAID controller.
Just read the compatibility charts for your RAID controller, many drives have footnotes with minimum drive firmware requirements and other odd behavior.
Re:almost clicked the link... (Score:5, Insightful)
LOSE LOSE LOSE LOSE! YOU WILL LOSE DATA!
Sorry... I'm usually a calm rational person. I almost never become a grammar-nazi, spelling nazi, or troll. It's just that I see this so often I'm afraid one day Webster will just give up and switch the definitions of Lose and Loose.