General question about Timeshift..[solved]

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Ricker
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General question about Timeshift..[solved]

Post by Ricker » Wed Apr 18, 2018 9:44 pm

Hello,

I want to know if Timeshift creates one restore file and will modify this restore file by writing over the original saved file or will Timeshift create several timeshift restore files..??


Thanks
Last edited by Ricker on Thu Apr 19, 2018 10:48 pm, edited 2 times in total.

Mattyboy
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Re: General question about Timeshift..

Post by Mattyboy » Wed Apr 18, 2018 10:01 pm

The very first image it creates will be everything apart from home files. The next 'image' and all thereafter will only save any changes you make to the system and create links back to the original image for unchanged files.

If you deleted the first image you would break the whole 'chain'. Basically.

Around 15GB is used in total for five snapshots. A partition of 20GB is more than enough for 'normal use'.

Ricker
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Re: General question about Timeshift..

Post by Ricker » Wed Apr 18, 2018 11:13 pm

My Linux Mint partition is 20GB. and with regard to disk space 10.3GB of 18.3GB Free...

Question is do I need to increase the partition size??





https://www.youtube.com/watch?v=qh08GvrUivc

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AZgl1500
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Re: General question about Timeshift..

Post by AZgl1500 » Wed Apr 18, 2018 11:43 pm

You can set the number of files you want it to retain, it will then delete the oldest file and create a new one.

IIRC, the stock setting is 5 backups.
I do mine manually to an extUSB HDD so my procedure is a bit different, and my USB HDD is 2.3TB so space is no concern for me.

I also make detailed notes in the label of each Timeshift that I create ( tell it to create )

The 1st run took quite a long time as I recall.
Subsequent runs usually take less than 2 minutes to completion.


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slipstick
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Re: General question about Timeshift..

Post by slipstick » Thu Apr 19, 2018 12:10 am

Mattyboy wrote:
Wed Apr 18, 2018 10:01 pm
If you deleted the first image you would break the whole 'chain'.
It won't break the chain. If a file is unchanged in several snapshots, there is only one copy of the data, but each snapshot will have a hard link to the data. Any snapshot can be deleted and the data will remain as long as there is at least one hard link to it. The chain is only broken when every snapshot with a hard link to that file has been deleted.

Mattyboy wrote:
Wed Apr 18, 2018 10:01 pm
Around 15GB is used in total for five snapshots. A partition of 20GB is more than enough for 'normal use'.
I'm using about 17GB for 10 snapshots, and if you keep, for example, 2 monthly, 3 weekly, 5 daily, and 2 boot, maybe a few hourly, with maybe a couple of "on-demand" snapshots, you could easily have 12-15 snapshots. I'd recommend more like 30 GB at minimum.
In theory, theory and practice are the same. In practice, they ain't.

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AZgl1500
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Re: General question about Timeshift..

Post by AZgl1500 » Thu Apr 19, 2018 3:32 am

I do only On Demand snapshots,

I think hourly is pure overkill. Unless you are a developer.

Daily might be okay, if the Timeshots are saved on an internal partition separate from the OS partition.

to me, to keep Timeshots on the main HDD is pure folly.

If you aren't fooling around with the system, why be making hourly snapshots, or for that matter, even daily snapshots.

If I add something, I make an ON Demand snapshot and leave it at that.
My backup HDD is a USB and it does not stay attached to the laptop if it is not immediately required.

I run Aptik once in a while, probably will tonight as there have been a lot of changes in the last 3 or 4 days.

My data is also saved the the UDB HDD, so if the laptop suffers a hard crash, I can put it back together very quick.

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Re: General question about Timeshift..

Post by Cosmo. » Thu Apr 19, 2018 5:08 am

The needed space for snapshots depend from 2 factors:

1. How big is the system. Not the size of the partition, but the actually used space.

2. How much gets changed in the system.
Too give a scenario, let us assume, that you have set to do hourly snapshots. Now the hour has passed, that there did not happen the least change in the system. Result: TS recognizes, that the previous snapshot is still totally up to date and does not even create a new snapshot.
Now an hour later let us assume, that only one file had been changed. TS will create a new snapshot, but all except this one file (which gets of course backed up) will be only hard links for the already existing back-ups. Hard links need zero space. But they make the new snapshot fully complete, even if the older snapshot should get deleted (automatically or manually. If you think this scenario further you can easily imagine, that you can store very many hourly snapshots with rather few space occupied by them, because usually the system changes from one hour to the next are very small.
If you now change in the scenario from hourly to daily snapshots, the differences between 2 consecutive snapshots are typically far greater, so more space is needed. Say you keep 5 snapshots: With hourly snapshots they will most likely cost hardly more space than the first one, with 5 daily snapshots the needed space is much greater. If you use weekly or even monthly snapshots, the difference between 2 consecutive snapshots will be very noticeably increase and the needed space for 5 snapshots will increase accordingly.

With the default setting (5 daily snapshots are kept) 30 GB will likely be enough, with 50 GB you should be on the safe side. Those values are true for a system with rather few additional software installed. Users, who install much software should consider to give more space for the snapshot partition.

Users, who include home in the snapshots - usually not recommended - will need dramatically more space for the snapshots.

Short end: The needed space cannot be defined with a single value.

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