How can Yahoo offer so much storage space for email?

Question

Yahoo offers 1GB?

If the max size of a hard disk is 500GB they would need a new hard disk for every 500 users that are signed up. And they have millions of users.

What's the trick?

Answer 1

Hands up how many people here have used all of their 1gb allowance?
Oh good none of you

I'd be surprised if I've actually used more than 20mb of mine. I remember when YM was initially only 1mb (and Hotmail's big selling point is that it offered TWO mb!)... then 5, and 11.... and stayed at 11 for donkeys years before suddenly jumping, after the arrival of the dreaded GMail.

It's known as a quota system, where you don't actually have a fixed space on the disc, your stuff just all goes into a folder or an archive file that's part of a big distributed storage array. They may offer you a maximum of 1gb, but the discs they buy and the average space allocation per user is based on some statistical analysis to give a rough guessimate predicition of what a typical person might burn through in a year. Call it 20mb, with some people using a few hundred megs, others barely making it to one. Your space requirements have now been slashed by a factor of fifty and you can get 25,000 users into one of those mammoth hard discs.

They could, theoretically speaking, offer you nearly unlimited storage (certainly several terabytes out of the *enormous* total) and still have a workable system.... if everyone was honest. The 1Gb limit is to stop the usual conceptual Handful Of Miscreants abusing it and leaving no space for anyone else.

Besides, and especially in business terms, storage space is dirt cheap these days. How else would I be able to buy a brand new 20gb mp3 player for £90? A server spec hard disc of about 75gb (high-speed ones like that are smaller for some reason) is only about £50 these days. If, once again, you assume that to be about 3750 people, that's not even 2p per user. They can make that back with a couple of banner ads that the user sees on logging in. Job's a goodun.

(Same reason, really, that Google can offer their "Maps" and "Earth" services, or any online seach engine such as Yahoo can work these days... if you have even a comparitively paltry ten grand to blow (might have got you, in the early 90s, the storage space represented now by a couple of Blu-Ray discs) you can afford such a mass of hard drive space, and the rather simple fileservers to manage it, that satellite mapping the entire planet at 10 centimetre resolution becomes more of an administrative than a technical problem)

Answer 2

Y! mail uses Netapp Filers for mail storage (there is a Netapp banner on the Y! mail page). Y! has many many terrabytes of storage that are allocated as needed to mail users.

Filers use RAID (redundant array of independent disks). In RAID data is "striped" across multiple disks for redundancy, while at the same time storing parity (Raid 3+) data for data recovery. Many hard drives can be striped together to create very large multi-terrabyte volumes. Most Netapp filers have a volume limitation of 12TB, but you can have multiple volumes on one netapp. Drives are stored in disk "shelves" which are connected via fibre-channel to the "head" which is the control unit. Data can be exported from the filer via iSCSI, NFS, or SAN.

If a user is inactive for four months or more, the space reserved for that user is deallocated and allocated to another user.

Answer 3

Normally any user cant use full capacity in a day. They have a software which deducts which user is requiring more space at a given time. The space is allocated accordingly. Although its keeps showing that you have a particular amount empty space in your email account.
A simple logical is like of banks. Everyone has a account in a particular bank & no one takes out cash all together at one time. If it happens then the bank will go bankrupt in a day. This logic applies to all email users.

Answer 4

Not every user uses their E-Mail. Not every person with E-Mail uses even close to their gig. There is new storage technology that makes storing Terabyes a walk in the park - not just hard drives but tape drives and other media storage. Plus, add compression to all of that and you realize it's not as farfetched as you would think.

Answer 5

They are using the unused space from everyone's home computers. Probably lots and lots of servers.

Answer 6

500GB is just what is commercially available to guys like you & I. Terrabyte is the next generation of storage.

Answer 7

not everyone uses their emails so the space can be divided equally amoung those who do use it and the emails don't even really take up that much space.

Answer 8

servers!!! a server can hold more space!! ur thinking at pc level. Servers are totally different. there are servers for backups, email, and other things as well.

Answer 9

To get people to use their service, it's smart of yahoo to offer more than "hotmail".

Answer 10

they have several terrabyte drives and not just 500 gb drives