AW: AW: RAID greater than 2TB on Fedora Core 3

[Rick Stevens]

Masopust Christian wrote:
> 
> hello rick,

Hi!  At the risk of starting another flame war, Christian, we prefer
bottom-posting here on the list.

> first thanks a lot for this detailed explaination!

You know me...I'm nothing if not bombastic!  :-)

> but (maybe stupid...), if it's possible to configure
> the blocksize of my raid, it should be possible to access
> greater raids than 2TB, right?

Uhm, hmmm.  Good question.  I've never tried it.  I don't know if the
mkfs utilities query the block size of the device to set up their inode
tables or not (I'd have though that they'd have to).  I suppose you
could give it a whirl and find out.

If you try it, let me know, willya?  I don't have any equipment handy at
the moment that I can sacrifice for an experiment (all our equipment is
busy right now and all my money is tied up in debts!)

> -----Ursprüngliche Nachricht-----
> Von: fedora-list-bounces at redhat.com 
> [mailto:fedora-list-bounces at redhat.com] Im Auftrag von Rick Stevens
> Gesendet: Montag, 04. April 2005 22:08
> An: For users of Fedora Core releases
> Betreff: Re: AW: RAID greater than 2TB on Fedora Core 3
> 
> Masopust Christian wrote:
>  >
>  > Hi Rick,
>  >
>  > is it really (nowadays??) a problem of SCSI-controler?
> 
> No, it's the SCSI protocol.  SCSI allows 4 bytes (32 bits) to specify
> the block number on a device, or 4,394,957,296 blocks.  Given that most
> disks use a 512-byte block, that's:
> 
>         4,394,957,269 * 512 = 2,199,023,255,552 bytes
> 
> or 2TB.  And before people jump on me, it's an unsigned 4-byte block
> number.  A signed value would make no sense--how do you access a
> negative block number?  I hear that the latest SCSI spec addresses this,
> but I have no idea when (or if) it will be released and how long the
> manufacturers will take to implement the new spec (if ever).
> 
> As an aside, the old 2GB file size limit was caused by using a signed
> 32-bit value as the second parameter in an lseek() (2^31 is
> 2,147,483,648, and that's in bytes--not blocks and it was signed to
> allow you to seek backwards from the current postition).
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- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
-                                                                    -
-   To understand recursion, you must first understand recursion.    -
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