RE: Large File support and blocks.

From: Linda Walsh (law@sgi.com)
Date: Thu Aug 31 2000 - 15:46:36 EST


> It is propably from reasoning of:
>
> "there is really no point in it, as at 32bit systems
> int and long are same size, thus same limit comes
> with both types."
>
> At 64-bit machines there is, of course, definite difference.

---
	There ya go again -- confusing the issue with facts.  Compare
and contrast the appropriate 32 and 64 bit values.  Using a 'long long'
on ia32 for comparison vs. an int.

Yes, with larger cluster sizes you can get larger virtual file sizes, but that's only pushing the problem a bit further back. Is it possible, I think there's an IRIX product to do this, CXFS' which can take an existing HD and allow you add-on more Hard disks to form a bigger and bigger drive. So -- maybe this is flawed, but I could easily see the mistake of starting out with a 1 K block size on your first HD, but then not being able to 'grow' it beyond a 2T limit. Some of our larger customers have had files larger than 2T -- customers exist today that use that functionality -- I have no idea what blocksize they use -- depending on their usage -- 4K might be reasonable, but if what you are doing is skipping around in a large database file and doing alot of small reads, 4K blocksizes might be less efficient.

If our customers were doing this over a year ago (which they were), it's not gonna be long before the practice spreads....growth is a virus... it keeps spreading...:-)

-l

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