... but my PC at home has a terabyte!
May. 27th, 2008 06:40 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
sobriqueOne of the things I get from time to time, is complaints about price and availability of storage in our SAN.
We have a large storage array - some 200Tb. The cost per gig, is ... well, I haven't checked recently, but it's high. It's a lot more than you'd pay for a 500Gb SATA drive at PC world.
So every now and then we hear the 'but I could buy that way cheaper'.
And ... yes, if all you wanted was a box of bytes, you could indeed get it way cheaper.
Thing is though, and enterprise storage array, has several things that your home PC doesn't:
15K RPM fiber channel drives. They're fast data rate, and fast seek drives.
64Gb of cache. (Yes, that's not a typo. This array has MASSIVE amounts of cache)
4Gb end to end, of Fiber channel bandwidth.
No single point of failure architecture - there's at least two of everything, and it can manage concurrent activity on multiple ports/devices, and gracefully fail.
Internal bandwidth of about 128Gb/s. (Not that this is a meaningful number in real use, but everything internally is multiply cross-connected).
High performance RAID controllers, which can actaully cope with 2000 physical drives at once.
And then there's the supporting architecture:
Fiber Channel network - the SAN is a fiber optic high speed, low latency network. Those are expensive. We're talking about £1000/port kind of expensive. You'll need at least two per server, sometimes more. And then we need to extend it out, and add new switches.
Remote replication - we don't have one volume with your data. We actually have 4. We have a local replica that we use to backup. We have a remote replica that we use for disaster recovery. And we have a remote replicata that we use for backups. Oh, and we use a LOT of bandwidth to keep those remote disks in sync with your local disk.
Backups. LTO3 tapes are about £50 each. And your 'terabyte' needs backing up every day.
Network throughput to the backup server - multiple servers backing up 'a few' terabytes every day, adds up pretty quickly.
Support contract - 24/7 4 hour response isn't cheap. But that's what we get.
Host infrastructure - your server needs 2 fiber channel controllers, they're expensive. The multipathing software for them, to allow them to concurrently use multiple ports also comes with a price tag.
So yes. Your disk from PC world is cheaper, byte for byte, than our SAN storage. But y'know, garden sheds are cheaper than mansions too.
We have a large storage array - some 200Tb. The cost per gig, is ... well, I haven't checked recently, but it's high. It's a lot more than you'd pay for a 500Gb SATA drive at PC world.
So every now and then we hear the 'but I could buy that way cheaper'.
And ... yes, if all you wanted was a box of bytes, you could indeed get it way cheaper.
Thing is though, and enterprise storage array, has several things that your home PC doesn't:
15K RPM fiber channel drives. They're fast data rate, and fast seek drives.
64Gb of cache. (Yes, that's not a typo. This array has MASSIVE amounts of cache)
4Gb end to end, of Fiber channel bandwidth.
No single point of failure architecture - there's at least two of everything, and it can manage concurrent activity on multiple ports/devices, and gracefully fail.
Internal bandwidth of about 128Gb/s. (Not that this is a meaningful number in real use, but everything internally is multiply cross-connected).
High performance RAID controllers, which can actaully cope with 2000 physical drives at once.
And then there's the supporting architecture:
Fiber Channel network - the SAN is a fiber optic high speed, low latency network. Those are expensive. We're talking about £1000/port kind of expensive. You'll need at least two per server, sometimes more. And then we need to extend it out, and add new switches.
Remote replication - we don't have one volume with your data. We actually have 4. We have a local replica that we use to backup. We have a remote replica that we use for disaster recovery. And we have a remote replicata that we use for backups. Oh, and we use a LOT of bandwidth to keep those remote disks in sync with your local disk.
Backups. LTO3 tapes are about £50 each. And your 'terabyte' needs backing up every day.
Network throughput to the backup server - multiple servers backing up 'a few' terabytes every day, adds up pretty quickly.
Support contract - 24/7 4 hour response isn't cheap. But that's what we get.
Host infrastructure - your server needs 2 fiber channel controllers, they're expensive. The multipathing software for them, to allow them to concurrently use multiple ports also comes with a price tag.
So yes. Your disk from PC world is cheaper, byte for byte, than our SAN storage. But y'know, garden sheds are cheaper than mansions too.
