Sometimes I do projects that require editing a bunch of photos on the external drive, so it's not only archival.
Also, I use the external drive to backup:
- Boot drive
- Active photo drive (the Lacie Little Big Disk)
- The photo archive
So I need four separate partitions (photo archive, boot backup, active photo backup, photo archive backup).
I guess this could be done with a two drive USB 3 enclosure, with one drive as photo archive, and the other split into 3 partitions: archive backup, active photo backup, and boot backup?
Would USB 3 be fast enough for the occasional photo projects where I need to edit photos from the archive on the external drive?
If you want to maximize performance. On the new iMac when you get it.
Boot Drive: SSD large enough for your OS and Apps. Apple generally uses a very fast SSD for this. I believe currently they use the Samsung SM951 AHCI. I wouldn't be surprised if the next uses either the SM951 NVMe or SM961 NVMe.
Active Photo and Photo Archive: Consolidate onto an external Thunderbolt 2 SSD 1TB is probably large enough for your use. Get an enclosure only so you can pick out a higher quality model like the Samsung 850 Pro or Sandisk Extreme Pro or some other which uses MLC memory. Samsung uses more efficient 3D V-Nand MLC I believe the Sandisk still uses 2D memory. Anyways the idea here is that all your photo work is lightning quick. Very little wait time for a database to load. Anything faster than Thunderbolt 2 won't matter as even dual SATA SSD's can't saturate the BUS. SATA III is too slow. If faster M.2 options were available you could. I've only seen that for USB 3.1.
As most Thunderbolt enclosures are two bay at the least. You can get the 1TB SSD and enclosure. Then if or when needed add a second SSD.
Backup Drive: As this sounds work related. The rule of thumb is to have one on site and one off site backup. That way your data is safe. A single backup isn't secure as the drive could fail during a restore. More likely is the drive being taken out with the computer by a catastrophic event. Possibly by lighting strike, flooding, fire or theft. The easiest option is an offsite backup service as an emergency copy and a local hard drive backup for a fast restore. At the very least use a fire and water resistant safe, bolt it to the floor and rotate the backups regularly. I'd do the single large drive with multiple partitions or use Time Machine and not bother with partitions. Then have either the second rotated duplicate backup or offsite backup.
Best part is your can use those parts now and move them to the new iMac whenever it comes out. However, if you buy now you will likely have to buy a Thunderbolt 3 to 2 adapter. Alternatively, you can buy one of the few Thunderbolt 3 enclosures but still have to buy the adapter. Otherwise live with degraded SSD performance over USB 3.0 in the meantime. Which is still faster than any hard drive. If you can find a Thunderbolt 3 Enclosure which allows you to connect via USB 3.0 not one which just adds USB ports acting as a dock.
As for USB 3.0 being fast enough for a hard drive. Yes it is. No single hard drive can come close to saturation the USB 3.0 BUS.
Yes the proposed solution is a bit more costly. Time is money after all. If you could decrease the time you spend waiting for the computer by even 5%. The external SSD will more than pay for itself.
