File Compression

seekermeister said:

kado897 said:

Tricky but then I am paranoid about backups. I suppose that disks are more reliable than the used to be but...

I don't know that disks are any more reliable. Even though you can verify the writes, I still have had some that didn't work, and also you have to consider the possibility of a disk getting damaged. I prefer the idea of backing up to a hard drive. The hard drive could go bad, but the odds aren't too great of two drives going bad at the same time (unless you have my luck).

EDIT: I just thought of another possibility...I have another Seagate 500GB 7200.11 in the closet, that needs to be RMAed, but since I received a series of bad replacements from Seagate, I had resigned it to the closet instead. I suppose that even if I got another bad replacement, it might last long enough so that I could split the video archive in half between two drives, and the only cost would be the shipping...I don't know.

Yes that's the theory behind raid. In a commercial installation if one disk in the set fails you can hot plug a replacement and it will all sort itself out. One IBM raid system we used even had the ability to have standby disks automatically swap in if a disk showed any signs of failure.

seekermeister said:

Yes, I could run it in raid, since my external enclosure does have raid capability, but I have never been too fond of raid. Somehow, the idea of continously using two drives to do the job of one seems a bit costly. I guess it is another possibility though.

That is why large installations use raid 3 or 5. You need fewer disks than mirroring.

seekermeister said:

Don't know what you mean, because as far as I know, all raid levels require at least two disks...sometimes more. Mirroring might have an option for a spare drive, but it only requires two.

Raid 5 uses five disks to hold the equivalent of 4 volumes with the data striped across all five disks. There is is sufficient redundancy using checksums that if any one disk in the group fails then the data can be reconstructed in real time so that it can continue to operate as 4 volumes. When the failed disk is replaced the group automatically reconstructs itself and the redundancy is restored.

seekermeister said:

There is one aspect to mirroring that I hadn't thought about. As it is now, I have to move the drive with the videos between computers, depending on where i want to watch them. If I setup a mirror, I could move one of the drives to the second computer, also setup on mirroring, and each could use a single drive, until I needed to sync them, by putting them both together in the raid. Wouldn't that work?

I don't think mirroring works that way. Mirroring is a continuous process with both drives being written at the same time. The only syncing takes place when you first set it up or replace one of the disks. You could of course network the computers and use one as a server for the videos so you could watch on either.

seekermeister said:

Yes, I could, but I was having some problems with getting the network to function properly, and lost interest. I know that if a drive fails in a mirror, that when a new drive is installed in it, it will rebuild the mirror by copying one drive to another, but I don't know that it would simply sync the contents or not.

I think you are right it would be a copy since the new drive is empty except that you can continue to use the mirrored drives while it is copying in any decent system.

seekermeister said:

mickey megabyte said:

+1

they're very highly compressed already.

the good news is that hard drives are amazingly cheap these days. :)

The hard drive that I would want to buy, is another of the same model that I have gotten 3 lemons in a row on, and it was not cheap. Does any of your cheap 1 TB drives have SATA III and a 64MB cache?

Hi seekermeister - FYI - You can get a 2 TB 7200 rpm Western Digital (WD) Caviar Black internal drive for about $175 - Don't know whether you would consider that cheap or expensive. They work great. :):):) It has a 64 MB Cache.