Re: ext2/3: document conditions when reliable operation is possible

From: Pavel Machek
Date: Mon Mar 23 2009 - 06:57:51 EST


On Mon 2009-03-16 19:40:57, Sitsofe Wheeler wrote:
> On Mon, Mar 16, 2009 at 01:30:51PM +0100, Pavel Machek wrote:
> > + Unfortunately, none of the cheap USB/SD flash cards I've seen
> > + do behave like this, and are thus unsuitable for all Linux
> > + filesystems I know.
>
> When you say Linux filesystems do you mean "filesystems originally
> designed on Linux" or do you mean "filesystems that Linux supports"?

"Linux filesystems I know" :-). No filesystem that Linux supports,
AFAICT.

> Additionally whatever the answer, people are going to need help
> answering the "which is the least bad?" question and saying what's not
> good without offering alternatives is only half helpful... People need
> to put SOMETHING on these cheap (and not quite so cheap)
> devices... The

According to me, people should just AVOID those devices. I don't plan
to point the "least bad"; its still bad.

> > + hdparm -I reports disk features. If you have "Native
> > + Command Queueing" is the feature you are looking for.
>
> The document makes it sound like nearly everything bar battery backed
> hardware RAIDed SCSI disks (with perfect firmware) is bad - is this
> the intent?

Battery backed RAID should be ok, as should be plain single SATA drive.
Pavel
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