We often need external disks to extend our main workstation or notebook computers. There are at least 3 different use cases:
- Backup
- High speed data access (e.g. for video)
- On demand data
Backup
In our experience disks that connect via USB 2 are just fine for pure backup and they are the cheapest solution. We use Chronosync to mirror our main data to different USB 2 backup disks (we never think that only one copy is good enough).
High Speed Data Access
Right now we don't feel the urgent need. If needed multiple RAID-0 connected drives (data are striped over 2 or more disks) would be it. To utilize the full speed eSATA connections are the best choice (maybe USB 3 in the future).
Note: Never use RAID-0 drives for backup or critical data. If even one drive fails all data are lost.
On Demand Data (e.g. Images)
We have right now 75,000 images in our Lightroom catalog. This includes the RAW files from 2000 till today. It is no surprise that the older RAW images get way less used than the the more recent ones. That is why we have the older RAW files on an external disk that we only power up on demand. For our work a Firewire 800 interface is just what we need (USB 2 is too slow for random access). Even our main current images are on a FW800 drive that is permanently connected.
We settled with OWC Mercury Elite-AL Pro Disk Enclosure:
It features these ports:
- eSATA
- 2x FW800 (can be used with FW400 using special cables)
- 1x FW400
- USB 2
We only got the enclosure and added the disk (2TB) ourselves (very easy to do).
Note: We like disks that don't get too hot. The advantage of the enclosure only option is that you can use the disks of your choice (we use mainly Western Digital or Hitachi drives).
It may sound strange but we like to have the on/off switch and don't like that much other designs that only power on/off via the ports. We may want the disk to stay connected via the cable but only powered on on demand.
We did not measure any speed but in our experience the OWC enclosures have good FW800 speed. The enclosure is well built.
Conclusion
For our purpose (On Demand Images in reasonable fast access) the OWC Mercury Elite-AL Pro Disk Enclosure fits the bill at a fair price. |