[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Lengthy time for archive creation
--As of October 31, 2013 12:39:31 PM +0800, Hanxue Lee is alleged to have
said:
Thanks for the clarification, Daniel.
No problem. I'm just a fellow user. ;)
It's a good idea to send these replies back to the list, in case someone
else has a better answer.
On Thu, Oct 31, 2013 at 10:56 AM, Daniel Staal <DStaal@usa.net> wrote:
None of which is particularly relevant - the likely determinate of backup
creation time is network speed, of your connection to the internet.
It's not exactly abnormal, but it is a bit slow - that's around 300 KBps.
How fast is your ISP connection?
I was on a 5 Mbps (~625KBps) VDSL/fibre optic connection. Will test again
on a 10 Mbps connection in office.
I'll admit I don't know the overhead ratio here - as well as the difference
between theoretical throughput and actual for that type of link. You got
about half the speed of your link, it sounds like, which may be normal or
not...
Before creating the new archive at home, I did a --dry-run in office, and
I remember it took a few minutes. I assume --dry-run will take a matter
of seconds by calculating checksums on the existing data, and compared
with the checksums from existing tarsnap archives?
Something like that. I believe it does almost everything except actually
sending the data - and time could vary depending on what's in your tarsnap
cache and what you are doing. (It may have to fetch data, if your cache
doesn't have the relevant sections.)
I may be completely wrong here though.
No - Small daily changes will get deduped and only the changes themselves
will get sent over the wire. Only the first upload needs to have all
the data. Daily changes will be much faster.
Good to know this.
Best regards,
Hanxue
Daniel T. Staal
---------------------------------------------------------------
This email copyright the author. Unless otherwise noted, you
are expressly allowed to retransmit, quote, or otherwise use
the contents for non-commercial purposes. This copyright will
expire 5 years after the author's death, or in 30 years,
whichever is longer, unless such a period is in excess of
local copyright law.
---------------------------------------------------------------