I have been looking into syncing external hard drives with my Nexto. Transferring files from Nexto to mobile drives is an important part of my video backup process but seems hard to accomplish. Relevant info about compatible drives is scarce and outdated.

We would really benefit from a collection of up-to-date success / failure reports. Thierry Humeau hit gold with G-Technology Mini 500GB 5400RPM USB drives http://www.dvinfo.net/forum/nexto-di-mobile-storage-solutions/483058-nexto-di-sxs-transfers.html#post1557304
Which drive worked for you? Which did not? Tricks, work-arounds?

Some pieces of general info, for starters
-NVS2525, NVS2500, ND2700, ND2725 support 'Sync' function (copying to another USB drive)
-according to Nexto support, external hard drive has to be FAT32 formatted (code 0x0015: invalid FAT)
-Nexto provides "some" USB power, enough to "some" external USB hard drives
-Nexto seems to work with some USB cables and fail with others
-list of obsolete compatible hard drives Nexto DI - Next Generation Storage with Digital Interface (http://www.nextodi.com/en/support/view.php?bbs=en_faq&id=7)

One option to power up a 2.5 inch USB mobile disk would be via USB Y-cable and a powered USB hub - has anybody tried this?

LaCie Rikiki Go 1 TB, USB powered mobile drive, does not get enough power from Nexto 2725 Video Storage. When connecting these two for sync, Nexto shuts off.

I tested Nexto on battery power, and also on AC power. There are no other power options than USB for LaCie Rikiki Go.

You will need to power the ext. HDD separately. I have used it in the past and it works.

Thank you for the promising information Olakunle.
Would you remember which HDD brand did you use with your Nexto 2725?
Was your HDD formatted as FAT32 or NTFS?

Apparently most FAT32 formatted external drives with mains power "sync" all right, but some don't.
Most drives on USB power do not work synced with Nexto, but some do.
If only we had a list of names.

Especially on the road, the 2.5 inch USB powered drives excel, because they are much smaller and lighter than the mains powered external 3.5 inch desktop drives. It would be very beneficial to know which ones sync with Nexto.

I formatted the HDD to FAT32. it is 2.5" that I have been using for some time but was powered up with car charger that comes with the Nexto. I believe that any 2.5" or 3.5" HDD formatted to FAT32 with capability for external power will work, but I do not have success with all the USB powered HDD.
Hope that helps.

Here is a summary of my further efforts:

Sync works all right with my mains powered 2TB desktop LaCie Hard Disk, when Fat32 formatted. Desktop drives like this one weigh one kilo though, about the same as a laptop.

For a lighter set up, I purchased a cheap USB hub with AC power, and a USB Y-cable. First I tested the LaCie Rikiki Go 1TB. The disk seems to get power all right, its indicative light turns on, but Nexto 2725 still does not see it when trying to sync, and when occasionally finds the disk, gives various types of error messages.

Bought also Iomega Prestige Compact 1TB and powered it with the USB hub, but no luck. This failure was disappointing because Google tells a success tail about a similar combination - mileage varies.

My solution to backing up terabytes of video on the road is here: http://www.dvinfo.net/forum/nexto-di-mobile-storage-solutions/491779-backing-up-more-switching-nextos-internal-hard-drives.html#post1618376
Please continue adding your experiences to this thread if you test Nexto - external disk combinations.

If you using AC power for both Nexto device(ND2700/NVS2500/NVS2525) and USB hard drive, then Nexto can SYNC to any USB hard drive if that USB hard drive formatted to FAT32.

If you using portable USB hard drive which only operated with USB bus power, then check if the internal hard drive is 4200rpm or 5400rpm.
Nexto device can provide enough bus power for 4200rpm or 5400rpm hard drive when Nexto is AC powered, but cannot supply enough power for 7200rpm or more hard drive.
These 7200rpm high performance hard drive need a lot more USB power than specified in USB specification.

Larry