Source chain backup


Could someone either shed some light or point me in the direction of some documentation that would cover a situation whereby there was a catastrophic failure of the device on which a user’s source chain in located?

Many thanks.

Hi @jason!

I’m assuming you are asking what happens to the data (the entries inside the source-chains across the different happs) that were stored in that device.

Depending on how the different apps were designed, there are two distinct cases regarding the information on the source chain:

  1. Public/encrypted entries: your information won’t be lost, as the DHT (public space) will still store all the entries and their metadata.
  2. Private entries: your entries will be lost, as the DHT will only store the hashes of the entries.

To prevent permanent loss of your data in the second case, some time ago there was talk about a HoloVault app that you would run privately on all your devices (laptop, mobile phone, raspberri pi…). This app would replicate all your private entries only across your devices, so that if one of those is lost, the others would maintain them. This infrastructure app will take some time to build in my opinion, as this is not a holochain core feature, and I haven’t seen any efforts from Holo to build it.

Regarding your private key on that device, it will be lost, but it shouldn’t be hard to recover or revocate. I’m not an expert on this (I have to read the documentation yet) but here is a pretty complete guide on the DeepKey system that holochain uses to handle public/private keys:

As far as I know, there is no special documentation regarding this case of device loss, but rather explanations scattered around the guides/medium posts.

Let me know if you want some clarification on my points or further explaining,


yes at first i was thinking of a holochain conductor feature that exported all your source data to file … so you could do a manual backup… but I imagine there would be security concerns with that approach? of course it could be an encrypted blob of some description…

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Yes for sure the holochain conductor keeps your data stored somewhere in your hdd, that’s without doubt, actually I think there is a way to configure it in the conductor-config.toml. But this wouldn’t cover the case of total device loss, unless you have a cron-like backup to some secure private server.

Anyway, I think a happ with this functionality would work best, since it would be very easy to install and would automatically replicate all your data at create time.

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Hi @guillemcordoba - thank you for your reply.

Scenario 2 was the particular instance I was thinking of. I remember reading about HoloVault quite some time ago. It maybe worth considering as more hApps are hosted on mobile devices.

Early days so I’m sure this will be looked at in the future.

Thanks again.

Hey folks — thanks @guillemcordoba for jumping into this conversation. Some of the confusion about status and timelines comes from the fact that Art was always calling the source chain backup hApp ‘HoloVault’, but Philip was calling the Personas & Profiles hApp by the same name. Well, P&P is now P&P, and the backup app doesn’t have a new name yet AFAIK. It’s definitely still on the drawing board, but is taking second place to the effort to increase performance and move Holo Host alpha testing along.

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I imagine the same solution could be applied to creating an iCloud/Google app (notes, calendar etc) equivalent where you have access from any device…

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Is there any new update on this topic… specially case 2 ?