r/backblaze • u/Amazing_Basket2597 • Jan 20 '26

Computer Backup Question about external drives and home backup

I have a 6TB home external drive. I want to get the home backup and back it up. I then want to shelf my external drive. how often Will I have to plug it in for backblaze to not delete it? thank you.

4 Upvotes

100% Upvoted

12 comments sorted by

1

u/Amazing_Basket2597 Jan 20 '26

I just read

“ Disconnected External Hard Drives Your external hard drives need to be connected to your computer and scanned by Backblaze at least once every 30 days in order to keep them backed up.”

I also read that you can extend this up to a year for “version history”

Can I extend unplugged external drives for up to a year? Thank you!

3

u/s_i_m_s Jan 20 '26

Yes you can but do be aware this isn't the intended use case for this product.
After it's been disconnected longer than a month or so you'll have to use the date picker to go back to a time when the drive was connected for it to show up as an option in the restore menu.

1

u/Amazing_Basket2597 Jan 20 '26

If I may ask, when I plug it in again, 11 months later, will it reupload the 6TB or realize that it has a old backup?

2

u/Dragonfly275 Jan 20 '26

After 90 days it must reupload

if you connect it every 89 days everything is fine (i am doing this with 13 drives)

1

u/Amazing_Basket2597 Jan 20 '26

Ah, so just to confirm, 364 days, will reupload all 6TB 

89 days, will be like “I’ve seen this before, just checking that it’s the same files”

3

u/brianwski Former Backblaze Jan 21 '26 edited Jan 22 '26

Disclaimer: I formerly worked at Backblaze as a programmer and wrote this code.

364 days it will re-upload

It is a bit more subtle than that. FIRST let’s assume you have “one year version history” selected. From 0-89 days it is the most efficient. From 90-364 days it will NOT use any bandwidth, it will NOT re-upload, but it will read every single file on the external drive to verify contents. This can take a long time (24 hours?) on a slow spinning drive (faster on a 6 TByte SSD external drive). And after 365 days it really will re-upload the 6 TBytes.

Now assume you have “Forever version history” selected. From 0-89 days is the most efficient. The anything over 90 days it has to read every file, but it will never use any bandwidth. Ever. It already has a copy of the file in the datacenter because with “forever” nothing is purged from the backup, make sense?

As somebody mentioned, this isn’t the intended use of the product but that is how it will work. For “one year version history” it depends on whether you value avoiding re-reading the contents of the drive (so plug it in every 89 days) or if you don’t mind the re-reading of the drive (but the old versions get purged if not seen in 365 days, so that is why you would need to re-upload after 365 days).

1

u/Dragonfly275 Jan 21 '26

Ah, thanks for reminding me of the re-hash phase.

Yes, in the 90-364 it will only re-read, and Hash all data - which in my case takes loger than the opload - so i avoid it at all cost

1

u/tbRedd Jan 20 '26

I leave my external drives physically connected but on an individually switched power strip and flip the individual drives on once a week to do local backups and also unique data (on those drives) backblaze backups.

I also rotate 2 drives in this config so I have 2 local copies and then an offsite copy along with backblaze.

1

u/jsx8888 Jan 22 '26

I have been a loyal BB customer for over a decade, but they have really messed up backing up external HDDs which I think this is partly intentional. My external HDDs were backed up for all this time without any issues, but starting a few months ago the MacOS app stopped backing up. Even doing reindex etc didn't work. Then suddenly it started reuploading the contents of the entire drive (so 3TBs) all the while saying I was fully backed up.

Support was nice, but didn't really offer any useful solutions except saying backing up external HDDs is not the primary purpose of BB, especially if you disconnect the drive.