From: Mefford, Aaron (amefford_at_about-inc.com)
Date: Thu 31 Oct 2002 - 16:20:35 GMT
> -----Original Message-----
> From: Dave [mailto:djp_at_comm.it]
> Sent: Thursday, October 31, 2002 7:08 AM
> To: vserver_at_solucorp.qc.ca
> Subject: RE: [vserver] Quotas
>
> On Wed, 2002-10-30 at 16:52, Mefford, Aaron wrote:
>
>
> > As to the specific post, I am not sure that the hard line of not
> overbooking
> > is a good idea. While for many applications it would be a correct
> solution
> > there are some where it will not. Every ISP over allocates their
> available
> > resources. People do not care to pay for dedicated resources.
> > Additionally, with most services now being offered via resellers, it
> seems
> > unreasonable to not allow the reseller the same option. For instance,
> if I
> > sell virtual private servers, and joe buys a VPS with the intention of
> > selling individual web sites run within the VPS, I may or may not want
> to
> > allow Joe to oversubscribe his disk space, possibly even on a per VPS
> basis.
>
> If you allow overbooking of quota, then you could very easily do without
> quota at all. I'll try to explain why:
>
> Overbooking anything is a recipe for disaster which will happen sooner
> or later. I'm not talking about quota alone. Overbooking network
> connectivity or airplane tickets or disk space or any other limited
> resource is like selling an item you don't actually own. It can look
> appealing to sell 100gigabytes of space when you own only 50, but will
> create you much more problems when every customer decides to use what
> they're paying for. It is called bad business practice.
Of course if everyone decided to fill there quota on the same day a melt
down would occur, just as if everyone were to login to there internet
account and start hitting sites the same day. It is not bad business to
deliver just in time services, but rather bad business to buy more disk
space than your users actually use today.
>
> Believe, you don't want to sell 100gigs with 50% guarantee (it's a pure
> joke).
>
I currently have 6T and have sold 17T of quota and allocated and additional
57T of quota to free users (whom are definitely not paying for dedicated
space). It may seem like a joke to you but it is real business. This
follows the line that has been used since the beginning of the ISP business.
You need 1 modem for every 10 customers. If you have less people get busy
signals. If you have more resources are idle (money is lost). If you think
that is not the case review how many *SP's survived the dot bomb. I worked
for Excite_at_Home last year and while some services were appropriately
oversubscribed, others were not and because of that they did not succeed.
> Also, the point of using quota is to be able to delegate space
> allocation to the system in an automatic and guaranteed way. If you
> overbook, you'll have to look constantly on the disk space and allow for
> downtime for disk upgrade when necessary.
>
> Dave.
There are many uses of quota and guarantee can mean different things. I use
quota to guarantee that no single user can exhaust the available space.
This is an appropriate use of quota. Someone else may prefer to use quota
to guarantee that the customer has the space available to them whenever they
choose to use it. I would use this approach if I was looking at server
consolidation perhaps. Finally, if you have a good disk subsystem then no
downtime is required to increase capacity.