SCSI is limited to 2 terabytes

Adrian 'Dagurashibanipal' von Bidder wrote:
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Clinging to sanity, Nik Simpson mumbled in his beard:

How did you know I had a beard :-)


--
Nik Simpson

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Clinging to sanity, Nik Simpson mumbled in his beard:
Clinging to sanity, Nik Simpson mumbled in his beard:

How did you know I had a beard :-)

Well, and if you didn't have one, I'd claim a metaphorical beard for you, as
I can't well say you mumbled into your clean-shaved chin ... :-)

- -- vbi

- --
Today is Pungenday, the 55th day of Discord in the YOLD 3170

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"Nik Simpson" writes:

That's false. Both larger block addresses and larger block sizes
are supported -- both by the specification *and* by many devices.

OK, which deviuces, and which OSes, shouldn't be that hard to come
up with a list if they are so "common"

Well, UFS (from BSD, originally published in 1984) handles volumes up
to 1TB. UFS2 (as found in FreeBSD 5.x and NetBSD(?)) hangles larger
sizes.

If a 20 year file system can handle 1TB, what do you think an file
system released 2-3 years ago could handle?

maybe possible, to exceed the 2TB limit its certainly not common
practice and its not a big deal for the OS or HBA vendors since
customers wanting single disks 2TB are a very small minority.

Perhaps. However you can pick up 3.5TB for US$ 11,000:

http://store.apple.com/1-800-MY-APPL...ily=XserveRAID

Or 1TB for US$ 1,200:

http://www.lacie.com/products/product.htm?id=10118


How big are contemporary CAD files, or video files, or even
high-quality photographs from cameras like a Nikon/Canon? Never mind
some people's pr0n collection. :

--
David Magda dmagda at ee.ryerson.ca, http://www.magda.ca/
Because the innovator has for enemies all those who have done well under
the old conditions, and lukewarm defenders in those who may do well
under the new. -- Niccolo Machiavelli, _The Prince_, Chapter VI

David Magda wrote:
"Nik Simpson" writes:

That's false. Both larger block addresses and larger block sizes
are supported -- both by the specification *and* by many devices.

OK, which deviuces, and which OSes, shouldn't be that hard to come
up with a list if they are so "common"

Well, UFS (from BSD, originally published in 1984) handles volumes up
to 1TB. UFS2 (as found in FreeBSD 5.x and NetBSD(?)) hangles larger
sizes.

If a 20 year file system can handle 1TB, what do you think an file
system released 2-3 years ago could handle?


Handling a filesystem 1TB and handling a device 1TB are not the same
thing, people have been able to create multi-TB logicial volumes (by
striping across several LUNs) for some time, hence the need for filesystem
that can be spread across the those logical volumes. NTFS for example has
supported multi-TB filesystems for years, doesn't mean that they are
particularly common in production environments.


maybe possible, to exceed the 2TB limit its certainly not common
practice and its not a big deal for the OS or HBA vendors since
customers wanting single disks 2TB are a very small minority.

Perhaps. However you can pick up 3.5TB for US$ 11,000:

http://store.apple.com/1-800-MY-APPL...ily=XserveRAID

Or 1TB for US$ 1,200:

http://www.lacie.com/products/product.htm?id=10118


Of course you can have large amounts of storage for relatively little money,
doesn't mean that people are going out and creating multi-TB LUNs.


How big are contemporary CAD files, or video files, or even
high-quality photographs from cameras like a Nikon/Canon? Never mind
some people's pr0n collection. :

Again, in the vast majority of cases, not big enough to need multi-TB LUNs.

BTW, I do stand corrected on the SCSI limit issue, but I still don't think
that multi-TB LUNs are particualrly common.


--
Nik Simpson

On 09 May 2004 21:36:58 -0400, David Magda
wrote:

[ Snip ]

How big are contemporary CAD files, or video files, or even
high-quality photographs from cameras like a Nikon/Canon? Never mind
some people's pr0n collection. :

What do you mean "even" photographs??? g

A busy night for me might consume about 15GB of raw image files (Kodak
Professional). Add about double or triple that for processed
versions. And then start over...

(A raw DCS file from my SLR/n is ~14MB).

However, while a TB file system would be nice, the things move offline
quickly, and rarely get updated, so I can actually work well with a
100GB filesystem. The large files get moved to DVD, and smaller JPGs
remain on disk for catalog purposes.

Malc.

David Magda writes:

How big are contemporary CAD files, or video files, or even
high-quality photographs from cameras like a Nikon/Canon? Never mind
some people's pr0n collection. :

Well, the TASS project collects up to 10 CDs in a night per site, with
more to come.

A good digital back or drum scanner runs files up to a GB or so.

I don't think there is a limit on p0rn, but the Delft Uni collection
was said to be 700GB last I heard. Comp.risks should have the size in
the story of its destruction by fire.

--
Paul Repacholi 1 Crescent Rd.,
+61 (08) 9257-1001 Kalamunda.
West Australia 6076
comp.os.vms,- The Older, Grumpier Slashdot
Raw, Cooked or Well-done, it's all half baked.
EPIC, The Architecture of the future, always has been, always will be.

Veritas is shipping a file system for UNIX/Linux which will address up
to 8 Exabytes. They need a volume manager to piece together the SCSI
devices into such a large address space.

dave dickerson wrote:
Veritas is shipping a file system for UNIX/Linux which will address
up to 8 Exabytes. They need a volume manager to piece together the
SCSI devices into such a large address space.

And the Windows NTFS, as well as several other OS filesystems have been able
to do this for the best part of a decade or more, but max FS size != max LUN
size.


--
Nik Simpson

Nik Simpson wrote:
dave dickerson wrote:

Veritas is shipping a file system for UNIX/Linux which will address
up to 8 Exabytes. They need a volume manager to piece together the
SCSI devices into such a large address space.


And the Windows NTFS, as well as several other OS filesystems have been able
to do this for the best part of a decade or more, but max FS size != max LUN
size.



Yeah, I see that - NTFS max size is 16 Exabytes ... I guess that means
if LDM or other volume management can build a logical disk that size
then bobs-your-uncle. Anyone know the max size of a Dynamic Disk?

What are the practical limits for NTFS? Certainly chkdsk time and
backups / restores come into play. Also the data structures of the meta
data stop performing well as the number of files becomes very large.

What's the largest you've seen? I've seen around 800 GBytes ( using EMC
Metavolumes ), but I suspect there are much larger in-the-wild.

dave dickerson wrote:
Nik Simpson wrote:
dave dickerson wrote:

Veritas is shipping a file system for UNIX/Linux which will address
up to 8 Exabytes. They need a volume manager to piece together the
SCSI devices into such a large address space.


And the Windows NTFS, as well as several other OS filesystems have
been able to do this for the best part of a decade or more, but max
FS size != max LUN size.



Yeah, I see that - NTFS max size is 16 Exabytes ... I guess that means
if LDM or other volume management can build a logical disk that size
then bobs-your-uncle. Anyone know the max size of a Dynamic Disk?

I beleive it's not fully implemented to support 16 EB, but is well north of
2TB.


What are the practical limits for NTFS? Certainly chkdsk time and
backups / restores come into play. Also the data structures of the
meta data stop performing well as the number of files becomes very
large.


That's a problem for all filesystems when getting into the 2TB+ range,
chkdsk/fsck and directory metadata parsing are going to be an issue. On the
whole NTFS is pretty good at reasonable recovery times and uses a fairly
sophisticated directory structure.


What's the largest you've seen? I've seen around 800 GBytes ( using
EMC Metavolumes ), but I suspect there are much larger in-the-wild.

I've seen customers with 2TB & greater, but not many, and often using sparse
voulme managment techniques underneath so that they don't actually need 2TB
up front and can add physical capacity as required without having to expand
the FS.


--
Nik Simpson