Re: Filesystem recommendations
Ron Johnson put forth on 4/26/2010 2:37 AM:
> On 04/26/2010 02:14 AM, Stan Hoeppner wrote:
>> Mark Allums put forth on 4/25/2010 1:19 AM:
>>
>>> (Why? ext3 and 4 are exceptionally well supported by Linux and GNU. XFS
>>> will be, too, probably.)
>>
>> Are you kidding? XFS already is all of the things you mention. You
>> apparently need a history lesson.
>>
>> XFS went into production systems starting in 1993 on SGI's Indy
>> workstations. XFS was GPL'd by SGI in 2000, and was in Linux mainline
>> just
>> before EXT3, since mid 2001 in kernel 2.4. It was used almost
>> exclusively
>> on the IA64 Altix machines. It took a while before non SGI customers
>> starting trying out XFS on i386 hardware.
> [snip]
>
> They couldn't have directly take the Irix code and brought it directly
> to Linux. It just wouldn't work, and Linus wouldn't allow such shimmed
> code into the mainline.
>
> So, while there's an XFS which is 17 years old, the Linux xfs code is
> "only" 9-10 years old.
Absolutely correct. I wasn't trying to imply the same exact code has been
around for 17 years. Hell if that was the case I wouldn't be using it.
Whilst the initial Linux porting effort was more than a simple recompile, I
don't believe it was a herculanean effort. Far more changes to the XFS code
have been made since inclusion in mainline than the changes required to get
from IRIX to Linux.
I actually saw a brief video interview of one of the SGI IRIX devs quite
some time ago in which he described the initial Linux port effort to get it
running on SGI's big Origin 3000 MIPS machines. They had to do this to
start validating how everything would run under Linux because they didn't
have the first Itanium Altix systems manufactured yet.
IIRC their testbed was a 32 processor Origin 3000 running MIPS R14K
processors. This was back before the Linux MIPS port project existed so
they were in essence creating the first Linux MIPS port as part of their
effort. He clearly stated that developing/maintaining a Linux MIPS port was
not in the cards for SGI, that this effort was strictly a validation effort.
He said it took about a week to get Linux booting on the Origin system, and
another week to get it stable. The first XFS port to Linux was part of this
effort. If it took only 2 weeks for the bulk of this effort, I can't
imagine they had to modify a ton of XFS code. IRIX was written in C as is
Linux, so the changes in XFS were probably fairly minor.
I'd venture to guess that the most significant Linux XFS changes were those
for the 32bit X86 code base. IRIX and thus XFS were born on 64bit MIPS RISC
CPUs. Moving that to a Linux 64bit Itanium environment was probably
relatively straight forward. Moving down to a 32bit platform probably
required a lot of code changes, as did the initial Linux 64bit ports up to
Alpha, HPPA, Itanium, and eventually MIPS64.
--
Stan
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