I need some guidance for a rapberry pi2 server

Zitat von Camaalot

Good explanation ryecoaaron. I always thought Raid was for backup.

The what is best : rsnapshot ou Snapraid ?

I'll explain the difference between the two solutions you mention, for this I'm going to simplify it to the extreme that I leave details out

Snapraid is used to ensure the integrity of your data (protection against silent corruption / bitrot). Since this solution normally keeps the data on the same system, its not considered a backup. e.g. if your system gets a virus, mallware, hack, electronic falure that kills your harddisks, etc this data is gone.... so not a backup.

rsnapshot is used to make copies of your data to another location or drive. Its benefit compared with just copying files is that it has the option to only copy changed files since your last update (saves storage space).

I believe you are looking to backup your data, then you should choose rsnapshot, its a very decent solution.

@ryecoaaron, good catch. Going to work on a article to explain the difference on the wiki.

Rsnapshot uses mirroring (like RAID1), which means that you have one data drive and everything is duplicated on the backup drive.
- Pro: If the data drive fails, you can plug in the backup drive an read the files.
- Con: You use 50% of drives for the backup.

SnapRAID uses parity (like RAID5), which means that you have 1 to 4 data drives for one parity drive.
- Pro: You use 20 to 50% of your drives for the backup depending on the total number of drives.
- Con: Recovering files from the parity data requires a manual operation on the command line.

If you have only 2 drives of the same size, then you might as well stick with Rsnapshot. For 3 drives or more, consider SnapRAID.

see my purple remarks to have a complete picture

Zitat von Nibb31

Rsnapshot uses mirroring (like RAID1), which means that you have one data drive and everything is duplicated on the backup drive.)
Its not mirroring (like raid 1) which consists of an exact copy of a set of data, rsnapshot is only refering to unchanged files using hardlinks (when snapshotting). Some nasties remove the file itself, making your backup unusable (virusses, damage sectors, etc).

- Pro: If the data drive fails, you can plug in the backup drive an read the files.
- Con: You use 50% of drives for the backup.
- con: no bitrot protection and such
This is pratically never true because anyone using this solution is making snapshots, basically rsynch with hardlinks to every unchanged file. So you always use more then 50%

SnapRAID uses parity (like RAID5), which means that you have 1 to 4 data drives for one parity drive.
- Pro: You use 20 to 50% of your drives for the backup depending on the total number of drives.
- Con: Recovering files from the parity data requires a manual operation on the command line.
- pro: bitrot protections and such

If you have only 2 drives of the same size, then you might as well stick with Rsnapshot. For 3 drives or more, consider SnapRAID.
Snapraid is an always connected, when you get hits with nasties (Fire, virusses, hacker,s systemmalfunctions, etc) its very possible that you lose all your data.

Snapraid is optimally used when you already have a regular backup or when a backup is a offordable solution for you. For important data I would choose rsnapshot over snapraid any day.

P.s. I use snapraid to, it basically is my dayly and weekly backup mechanisme, I make yearly full backups with rsync to a remote server and monthly snapshots using hardlinks. So nothing against snapshot, its just always connected and thus vulnerable.

Alles anzeigen

1. RAID is not a backup. If it has the word/acronym/phrase "RAID" in it, it is not a backup solution and you are risking losing all of your data. Yes, this means SnapRAID is NOT A FREAKING BACKUP.

2. Using rsnapshot for backup is only useful if it creates a complete copy of the data for you to disconnect and store elsewhere. If the "backup" drive remains connected to your system, it isn't a backup.

3. When it comes to backups, the correct strategy is 3-2-1. Three copies of all your data, in Two different formats, One of which is off-site. That could be spare drives and cloud storage, spare drives and tape, tape and cloud storage, etc. Personally I'm using a remote NAS at my parents' house about 4 hours away (therefore protected in case of most natural disasters) that uses Syncthing to keep up to date, and ZFS snapshots at both ends to allow for things like crypto virus recovery. Considering using Amazon Cloud Drive to add another layer.

This is only for sensitive/personal data like tax receipts from TurboTax, family photos, CrashPlan backups for all the PCs, personal documents, etc. I also throw in my ebook collection and config files for the routers switches and access points in my lab, because it's useful data that is low volume.

The rest tends to be OS install ISOs, media files, and other bulk data that I can re-download or re-rip if needed. (For media, re-rips from original constitutes the second format anyhow.)

So far the only thing here that really comes close to an actual backup is rsnapshot, and I can't even say that's the case if it uses hard links and expects to be connected to the original machine. I don't know, I've never installed it.

This is getting waaaaaay to technical for the asked question

The thread starter should use rsnapshot for now and read some more about backups&filecorruption/bitrot to decide if he needs more then only a backup (just a backup goes a long way and is much better then most people have).

Inline my comments for further technical discussion I tried to stay away from, this doesn't help the thread starter.

Zitat von ryecoaaron

@GreenBean Some of your comments are wrong and rsnapshot is not as vulnerable to viruses.
I'm not saying rsnapshot is specifically vulnerable, at least that was not my intention, it great. (i'm doing the same thing with a script that also does considers moved/renamed files).
Topic starter is talking about a single station solution, unless you have rsnapshot disconnected its prone to nasties, I still stand with my statement.

If you don't share any of the backup volume, how is the virus going to ruin the rsnapshot backups?
It feels like you are changing to context here. The topic starter is talking about a single station setup, you seem to be talking about a mutlistation station setup. That is a completly different discussion

I have rsnapshot running at a school I help and they have been hit by the crypto virus. Guess how many files we lost? None that were older than 1 hour because rsnapshot was setup to take hourly backups.
Unless you have rsnapshot running on a different computer you just had a lot of luck.

The first copy to the backup drive is not a hard link. ...
That why I said "when snapshotting'

How do you hard link across drives??

I didn't say you should or could... why are you saying this?

You can't. Only unchanged future snapshots will be hard linked to the first copy.
Thats what i basically mentioned already.

So, a virus removing the file will not ruin your backup.

removing the file itself from a complete backup removes it from from any linked snapshot, doesn't matter if its a user, sector error or anything else.

And yes, you use more than 50% but not much more unless you are constantly editing videos. Most people don't have 100% full drives. So, rsnapshot to another drive of the same size usually works well.
Every change adds the storage of the complete size of the changed file. 50% is very unrealistig when people have media files, do video edditing, raname files, move files, etc.
Changing a full-HD homevideo for example adds the full size to the backup lets say 12 gb extra storage

With remotemount, you can rsnapshot to a remote server as well.
Sure, what doesn't work remotely these days?

I will say once again that rsnapshot and snapraid are not competing services. snapraid is not backup and rsnapshot is not bitrot protection/redundancy. They can work very well together.
I said the same thing and still believe the topic starter's best choice is rsnapshot as adviced earlier.

Alles anzeigen

Zitat von wolffstarr

1. RAID is not a backup. If it has the word/acronym/phrase "RAID" in it, it is not a backup solution and you are risking losing all of your data. Yes, this means SnapRAID is NOT A FREAKING BACKUP.
We already made that clear, was unnecessary to mention it again.
p.s. It can remove the need for snapshot backups at x intervals though and in that manner replace a part of your backup. In my riskcalculation i'm using it to replace my daily b's and accepting the increased consequences. Its all about risk and impacts.

2. Using rsnapshot for backup is only useful if it creates a complete copy of the data for you to disconnect and store elsewhere. If the "backup" drive remains connected to your system, it isn't a backup.
Mostly agreed, but even a local backup is still a backup.

3. When it comes to backups, the correct strategy is 3-2-1. Three copies of all your data, in Two different formats, One of which is off-site. That could be spare drives and cloud storage, spare drives and tape, tape and cloud storage, etc. Personally I'm using a remote NAS at my parents' house about 4 hours away (therefore protected in case of most natural disasters) that uses Syncthing to keep up to date, and ZFS snapshots at both ends to allow for things like crypto virus recovery. Considering using Amazon Cloud Drive to add another layer.
There are other approaches to that might be better or worse, but 321 is certainly not the only approach.

This is only for sensitive/personal data like tax receipts from TurboTax, family photos, CrashPlan backups for all the PCs, personal documents, etc. I also throw in my ebook collection and config files for the routers switches and access points in my lab, because it's useful data that is low volume.
I'm backupping everything here for the family, except my commercial-media(games, video, music, books, etc).

The rest tends to be OS install ISOs, media files, and other bulk data that I can re-download or re-rip if needed. (For media, re-rips from original constitutes the second format anyhow.)
Same here

So far the only thing here that really comes close to an actual backup is rsnapshot, and I can't even say that's the case if it uses hard links and expects to be connected to the original machine. I don't know, I've never installed it.
It can push & pull, depending on your setup. But its been a long time since I used it, wasn't very good with renamed files, etc.

Alles anzeigen

I don't have time for such discussions either, I prefer discussions where someone (preferably me) learns something. This isn't such a discussion.

There are so many reasons that a local backup can get whipped/damaged, a few things that comes to mind:

• computer is bumped while running;
• Air intake get glogged in the summer unnoticed
• Motherboard fail (poof conductor might lead to poof backup)
• Powersupply fail (been there... :S)
• Sudden power failure might even do the trick in rare situaties
• Power Voltage Surges
• water damage
• fire!
• getting hacked (especially on default firewalls... if existing)
• getting a virus (jup they are there)
• other human errors
• etc.

Trusting only on local backups is really insane, doing a remote backups is sane.

I think you are misinterpreting my first message and your last reply has a totally different context especially mentioning the remote backup. At this point its not even clear to me at what point you disagree.

We both advice rsnapshot from the given options... great! Case closed

Zitat von Camaalot

Wow, Guys !

Guys?!?

Your welcome, nice to see such enthousiastic replies.

p.s. Sad to see that cute RPI leaving though, might be usefull for an offsite backup *ducks and runs for cover*.