How do I backup multiple drives to an 8TB drive?

Time Machine will backup all the drives to one backup drive but keep each drive separate. You can also use Time Machine or another backup utility that backs up each drive to its own partition on the backup drive.

Pretty much all backup utilities can do incremental backups that only backup the changes since the last backup. But do not attempt to backup to a disk image file.

Basic Backup

For some people, Time Machine will be more than adequate. Time Machine is part of OS X. There are two components:

The Time Machine preferences panel which is part of System Preferences;

A Time Machine application located in the Applications folder. It is used to manage backups and to restore backups.

Time Machine requires a backup drive that is at least double the capacity of the drive(s) it backs up.

Alternatively, get an external drive at least equal in size to the internal hard drive and make (and maintain) a bootable clone/backup. You can make a bootable clone using the Restore option of Disk Utility. You can also make and maintain clones with good backup software. My personal recommendations are (order is not significant):

1. Carbon Copy Cloner
2. Get Backup
3. Deja Vu
4. SuperDuper!

Visit The XLab FAQs and read the FAQ on backup and restore. Also, read How to Back Up and Restore Your Files. For help with using Time Machine visit Pondini's Time Machine FAQ for help with all things Time Machine.

Although you can buy a complete external drive system, you can also put one together if you are so inclined. It's relatively easy and only requires a Phillips head screwdriver (typically.) You can purchase hard drives separately. This gives you an opportunity to shop for the best prices on a hard drive of your choice. Reliable brands include Seagate, Hitachi, Western Digital, Toshiba, and Fujitsu. You can find reviews and benchmarks on many drives at Storage Review.

Enclosures for FireWire and USB are readily available. You can find only FireWire enclosures, only USB enclosures, and enclosures that feature multiple ports. I would stress getting enclosures that use the Oxford chipsets especially for Firewire drives (911, 921, 922, for example.) You can find enclosures at places such as;

1. Cool Drives
2. OWC
3. WiebeTech
4. Firewire Direct
5. California Drives
6. NewEgg

All you need do is remove a case cover, mount the hard drive in the enclosure and connect the cables, then re-attach the case cover. Usually, the only tool required is a small or medium Phillips screwdriver.

IF and only if all these drives are MacOS formatted drives (MacOS extended file system or HFS+) you can turn on the built-in backup system called Time Machine in System Preferences.

Specify the 8TB drive as the Backup destination drive. Specify that none of your drives are on the EXCLUDE list. if Time Machine ask to initialize the destination drive, that is as expected. Then go about your business -- it will take all afternoon and into the night, BUT you can use your Mac reasonably well for whatever you like while it runs.

On MacOS format drives, MacOS maintains the File System Event Store, a list modified folders. This allows Time machine to make its next backup really quickly. Rather than having to scan every file for its modified date, it can just consult the list of changed folders.

I would like to post a link to the wonderful Time Machine and MacOS site created by the late James Pond, but it currently offline.

All I will say about Time Machine is that it is easy to setup and use. Personally, I won't use it. I prefer using third-party backup software using incremental backups to a bootable clone. The latter can be a separate disk or a partition on a disk. Unlike Time Machine these backups can be used to replace a startup drive, are reliable, are faster than Time Machine, and use less disk space than Time Machine.

If the six drives you have were 1TB each, then you would need a minimum of 12TBs for the backup drive -at least 2-3 times the capacity of the disks being backed up. Your 8TB drive is too small.

Volume could not be unmounted.

It looks like that drive is actively being used for something -- like you might be running from a System on it, or Sharing its files.

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If you use SuperDuper and are familiar with it, that is probably what you should use for your big Backup.

I am not certain you need to partition this big drive. I would look into copying each drive into a folder named after the drive. if that is not easy, then copy the first drive, create a new folder, drop everything into the new Folder. Then copy the second drive, copy all its stuff into its new folder, and so on.

Then you get the largest possible free space, and no fragmentation issues.

Time Machine's big "claim to fame" is that it is the backup that actually gets done, because it works automatically and at low priority in the background, so that you don't have to set up a separate, convenient time to do nothing but backups. (There is no convenient time to back up and do Nothing else.)

The first full backup takes quite a while, but you don't give up the use of your Mac while it is working.

Another "cute trick" is that Time Machine.app, used to Restore, can show you exactly how a folder looked as of ANY still-available date&time for which there was anything backed up.

Time Machine requires at least 2-3 times that much capacity because Time Machine is not an incremental backup that overwrites old files. It is an archiving backup that keeps old and new versions so you can go back in time. For a Time Machine backup drive, you need from 12-18TBs. With an 8TB backup drive pretty soon you would run out of space and have to reformat the drive to start over.

Time Machine deletes older files if they have been deleted from the source when it needs space on the backup drive for a new incremental backup. Time Machine "thins" it's backups; hourly backups over 24 hours old, except the first of the day; those "daily" backups over 30 days old, except the first of the week. The weeklies are kept as long as there's room.

How long a backup file remains depends on how long it was on your Mac before you deleted it, assuming you do at least one backup per day. If it was there for at least 24 hours, it will be kept for at least a month. If it was there for at least a week, it will be kept as long as there's room. By default, Time Machine backs up hourly. That cannot be changed in Time Machine. There are third-party utilities that will modify the backup interval such as Time Machine Editor.

The Time Capsule sparse bundle grows in size as needed, but doesn't shrink. Thus, from the user's viewpoint of the Time Capsule, it appears that no space has been freed, although there may be space in the sparse bundle.

Once Time Machine finds it cannot free up enough space for a new backup it reports the disk is full. You can either erase the backup drive and start over or get a larger drive.

Unlike other incremental Backups, Time Machine does not immediately discard all the older versions of files. so it is storing more than just the latest version.

That is what allows it to do the "cute trick" it is named for, and show you every folder for any date&time for which any Backup data still exists.

Over time, it will start to discard complete older Backup sets from long ago. But if your drive is too small, it will have to do this constantly, and it is computationally and I/O intensive (it has to go fix links to older files in each successive Backup in the chain of older backups) This starts to become a pain.

aside to:

Kappy

I think this needs your input:

Pondini Time Machine Web site shows as "suspended"

.

Grant,

I never heard from the family about maintaining it or taking it over. If they have suspended it then I assume they don't wish for it to carry on.