3TB and Linux?

Giles Orr gilesorr-Re5JQEeQqe8AvxtiuMwx3w at public.gmane.org
Wed Jan 5 22:22:09 UTC 2011


On 5 January 2011 14:42, Lennart Sorensen <lsorense-1wCw9BSqJbv44Nm34jS7GywD8/FfD2ys at public.gmane.org> wrote:
> I see mentions of LBA32 which seems silly since LBA in the past has
> always been LBA28 for old IDE and LBA48 for modern IDE and SCSI, and I
> can't believe SATA would use anything other than LBA48.  Some people are
> talking about LBA64, which seems like nonsense.  They also claim LBA48
> can only do 2.8TB, which is wrong.  2^48 bytes would be 2.8TB, but LBA
> is sector addreses, so 2^48 sectors using 512byte sectors is 1430TB.
> It seems the real problem is some drivers only support 2^48 byte access
> for some reason.  Apparently some designs only support a 32bit sector
> number internally, which means 2^32 sectors of 512 bytes which is 2TB.
> Not an LBA problem at all though, since the interface is LBA48, just an
> internal design problem.

Today, a 2TB drive is "big."  In 1994 a 2GB drive was "big."  At that
rate, we can expect 2PB drives around 2027 and you'll be wanting LBA64
considerably before that arrives.  Preparing for the future doesn't
hurt, and doing it well in advance is a lot less painful than doing it
under pressure (witness IPv6 ...).

[Of course I'm making dozens of assumptions: exponential increases in
storage size will continue, sector sizes won't increase, etc.  But I
think the main argument stands.]

-- 
Giles
http://www.gilesorr.com/
gilesorr-Re5JQEeQqe8AvxtiuMwx3w at public.gmane.org
--
The Toronto Linux Users Group.      Meetings: http://gtalug.org/
TLUG requests: Linux topics, No HTML, wrap text below 80 columns
How to UNSUBSCRIBE: http://gtalug.org/wiki/Mailing_lists





More information about the Legacy mailing list