ZFS
Sam
sah at softcardsystems.com
Thu Sep 16 11:03:03 PDT 2004
On Thu, 16 Sep 2004, Gary Corcoran wrote:
> Sam wrote:
>
>> On Thu, 16 Sep 2004, Jan Grant wrote:
>>
>>> On Thu, 16 Sep 2004, Sam wrote:
>>>
>>>> Let's suppose you generate an exabyte of storage per year. Filling a
>>>> 64-bit
>>>> filesystem would take you approximately 8 million years.
>>>
>>>
>>> Hang on, I'm not sure I know where these numbers are coming from.
>>>
>>> 1PB is - what? 2^50 bytes? That looks closer to 2^64 than your
>>> figures indicate. I'd imagine an exabyte a year ought to be topping out
>>> after 16 years. I'm missing about half-a-dozen orders of magnitude
>>> somewhere it seems.
>>
>>
>> 1PB is indeed 2^50 bytes, but filesystems don't address on the byte,
>> but on the block (1K, 4K, 8k, ...). The numbers I'm using assume
>> the filesystem addresses on the sector, which is unrealistically
>> small. Jack it up to a 16K blocksize and you jump a few hundred
>> ZB in size.
>
> You have to be able to *seek* on a byte boundary. Hence doesn't a
> "64-bit" filesystem indeed mean "only" 2^64 bytes?
Only for the file you're seeking on.
Sam
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