Home
| Calendar
| Mail Lists
| List Archives
| Desktop SIG
| Hardware Hacking SIG
Wiki | Flickr | PicasaWeb | Video | Maps & Directions | Installfests | Keysignings Linux Cafe | Meeting Notes | Linux Links | Bling | About BLU |
I should discuss more what I want to do with LVM and maybe it makes more sense. First, the statement of problem. Hard disks are big and fundamentally slow. Suppose you have a 1TB hard disk. How on earth do you back that up? If you use a 1TB USB hard disk (USB 2.0) At best case, you'll get about 30MB/s. (You won't get that fast, but it is a good round number for discussion) 1TB is 1,099,511,627,776 bytes. At 30MB/s that's a little over 9 1/2 hours to backup. If you use a dedicated high speed SATA or SAS drive, you may get a whopping 160MB/s. That's 1 hour 49 minutes. Think now if you want to pipe that up to the cloud for off-site backup. With snapshots, you can back up a consistent state, as if your 2 hour backup happened instantaneously, but you are still writing a lot of data. However, there is a better optimization here. The snapshot device "knows" what is different. You don't have to really backup 1TB every time, you only have to backup the changes to it since the last full backup. I can't give too much away, but I think you get my drift. If the data only changes 5% a day, and you can track that 5% a day. You can make an effective backup of 1TB of data in 29 minutes to the USB drive. Think about it. LVM is more than capable of doing this.
BLU is a member of BostonUserGroups | |
We also thank MIT for the use of their facilities. |