>I'm looking into cloud backup options for a small business, they'd be looking at backing up ~150GB.
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>This will mainly be for secondary protection against disaster (fire, theft, earthquake etc.), they'll still have onsite backup to external media. Also for protection against CryptoWall-type malware.
>
>Anyone have any recommendations, for or against, the various providers?

Against Cryptos this will only help if you do store distinct / incremental backups (so not overwriting) , and the filesystem should have no acces to it. Or the old backups might end up encrypted as well.

IOW I think it's a good idea to have something on a non MS OS (just to protect it, makes it harder for maleware to have it several OS) that catches your "normal" backups and distribute them (encrypted with your key) to some external source. This might be some cloud service - or, as I do it, a cheap NAS on a friends location via VPN. So you will only loose what goes encrypted to "normal" backup.

BTW, the normal Cryptos need some time (several days) to encrypt your HDD, but the files are encrypted evern on a server. If an incremental Backup starts growing w/o visible reason (file changed due to encryption by Crypto) you know what to do next.
This is the Crypto on MS OS puts the data encrypted to SAMBA - but the linux machine will read raw data, the Crypto can not hook this side. -> Incremental Backup grows.

You might argue that an MS Server might do the same, but the problems with MS accounts vote against that.

My EUR 0,02