With the raging flame war going on about MUAs, I'm embarassed to mail this
with lotus notes, but, hey, its all I have at work.
Back on topic, I would have thought that package distribution was a one
time shot. Caches are for people who would otherwise download the
slashdot.org header graphic fifty times a day. Whereas each individual
debian machine should only have to download the latest perl .deb once in
it's "life". If I apt-get upgrade through my http cache, all I do is flood
the cache with megs of data I'll never download again.
I'm not sure about the overhead is minimal for less than a thousand
clients. I have 18 or so debian workstations at work. If it takes 5
minutes to transfer all the .debs to upgrade one machine, then I think it
would take a unicast system slightly less than 18*5 minutes (about 1 1/2
hours) to upgrade, vs 5 minutes for a multicast system to upgrade. A
unicast upgrade could be an "start it and go to lunch" process whereas a
multicast upgrade would be a "get a cup of coffee" process. If I had a
hundred machines to upgrade, the comparison would be even greater. Yeah,
wasting 17*5 minutes is not the end of the world, but why not try harder to
do better?
The concept of the system I'm discussing, is one "master" machine downloads
the .deb via http. Then it multicasts the .deb to all the other machines
at once. All of them are on the same subnet so some variety of layer 2
multicast / broadcast would work, although it would be nice to go beyond
the subnet if necessary.
I agree that the discussion about new installs points out that sometimes,
"pull" based systems have an advantage. I'm pointing out that sometimes,
"push" based systems have an advantage. And I'm motiviated because I
believe my situation at work is one of those situations where "push" is the
better answer.
Matt
Zimmerman To: debian-devel@lists.debian.org
<[EMAIL PROTECTED] cc: (bcc: Vince
Mulhollon/Brookfield/Norlight)
rg> Fax to:
Sent by: Matt Subject: Re: Rambling apt-get
ideas
Zimmerman
<[EMAIL PROTECTED]
t>
01/04/2001
01:45 AM
On Fri, Dec 29, 2000 at 11:11:01PM +0100, [EMAIL PROTECTED] wrote:
> Why not look at this from a different perspective? I don't know if it may
be
> useful or not for upgrading machines, but the multicast server would be a
> very nice thing for mass installations.
I still disagree. Multicast is the wrong solution. Multicast data is
basically equivalent to a cache with zero object TTL. Packets (objects)
are
stored (by a network device) until a client needs them (immediately), at
which
point they are served (multicasted/broadcasted) and expired (discarded)
