backing up wallet question

[CreamyPie]

Hello, If i back up my wallet on bitcoin qt and I have other computer with bitcoin qt downloaded too. If I paste my wallet.dat file on my other computer and I do some transactions, will my balance also updates on the first computer too? Can I run the same wallet on multiple computer at the same time? Anyone know? thanks.

[Michael Jackson]

what wallet you use ? check your email . downnload backup and save in flashdisk or save place who never can steal or copy your private key .
"if you have a lot BTC"

[CreamyPie]

what wallet you use ? check your email . downnload backup and save in flashdisk or save place who never can steal or copy your private key .
"if you have a lot BTC"

You didn't answer to my question, sorry.

[BurtW]

what wallet you use ? check your email . downnload backup and save in flashdisk or save place who never can steal or copy your private key .
"if you have a lot BTC"

I see you are new here so I will be nice.  The standard way to make a post is:

1) Read the question
2) Answer the question if you know the answer

What you did was:

1) Skip the question
2) Write some random stuff unrelated to the question

Watch this:

Hello, If i back up my wallet on bitcoin qt and I have other computer with bitcoin qt downloaded too. If I paste my wallet.dat file on my other computer and I do some transactions, will my balance also updates on the first computer too? Can I run the same wallet on multiple computer at the same time? Anyone know? thanks.

Balances are not kept in your wallet.dat.  The wallet balance is actually caclulated from the blockchain.  What is actually in your wallet.dat is just your private keys.  So, to answer your question, if you have multiple wallets that have the same set of private keys (the same wallet.dat file) then the balances in all of those wallets will be the same and will be kept in sync as each wallet calculates the balance from the set of private keys held in the wallet.dat file.

If you have any more questions just let me know.

[Abdussamad]

It's not a good idea to do this with a non-deterministic wallet. Each time you send bitcoins, bitcoin-qt generates new private keys to add to the key pool. These are entirely random. Eventually the two wallet copies will diverge and you'll have different private keys in them. It'll be very confusing and you risk loosing bitcoins.

If you want to share a wallet on different computers use either a web wallet or a deterministic one like electrum.

[BurtW]

It's not a good idea to do this with a non-deterministic wallet. Each time you send bitcoins, bitcoin-qt generates new private keys to add to the key pool. These are entirely random. Eventually the two wallet copies will diverge and you'll have different private keys in them. It'll be very confusing and you risk loosing bitcoins.

If you want to share a wallet on different computers use either a web wallet or a deterministic one like electrum.

Please listen to this very good advice.

I considered the OP's question to be hypothetical but now, reading it over again, it looks like this is something they might be thinking about actually doing.

Can I run the same wallet on multiple computer at the same time? Anyone know? thanks.

DO NOT DO THIS for the reasons stated above.  It can be done but a) you really have to know what you are doing and b) it cannot be done with the bitcoin-qt wallet.

[virtualx]

Hello, If i back up my wallet on bitcoin qt and I have other computer with bitcoin qt downloaded too. If I paste my wallet.dat file on my other computer and I do some transactions, will my balance also updates on the first computer too? Can I run the same wallet on multiple computer at the same time? Anyone know? thanks.

To backup export your private keys. If my understanding is correct, private keys are used to move the money - and in case your wallet fails, you can import private keys.

[Dabs]

You could use the same wallet.dat file if:

1. You backup the wallet.dat from the first computer.
2. Copy that backup to the second computer.
3. RESCAN the blockchain from the second computer.
4. Do whatever on the second computer.
5. Backup the updated wallet on the second computer.
6. Copy that updated wallet to the first computer.
7. RESCAN the blockchain from the first computer.

You can keep doing the steps above. You will essentially be using only one wallet.dat file, constantly being copied back and forth. The other computer has a "backup" of your older wallet.

OT, Cream Pies remind me of something else.

[ranochigo]

Hello, If i back up my wallet on bitcoin qt and I have other computer with bitcoin qt downloaded too. If I paste my wallet.dat file on my other computer and I do some transactions, will my balance also updates on the first computer too? Can I run the same wallet on multiple computer at the same time? Anyone know? thanks.

Yes. On both of your computer, when a transaction is made, it propagates among nodes. It will update the other client with the amount transaction. You can spend bitcoin anywhere as long as you have the private key. Private key is in backups, after downloading the full blockchain or if you use a lightweight wallet and restore the private key, your balance and transaction will update automatically. Bitcoin is basically about signing transactions, as long as you have the private key, you can sign and broadcast them, no matter how many wallets with that private key you run.

[bitpop]

For your convenient wallet use blockchain, for savings use armory which needs qt.

[catoboli]

I can also confirm that it will be displayed and work on both. I'm currently in the process of moving all my QT's from one computer to another, my main comp has an SSD and the blockchain is taking up a lot of info but for a little while they have been up and running on both.

[zulover]

Should we always have a recent backup all the time or and old backup will do?

[BurtW]

Should we always have a recent backup all the time or and old backup will do?

On bitcoin-qt you should backup every 50 [send] transactions or so and you must backup every 90 [send] transactions or so.

[zulover]

Should we always have a recent backup all the time or and old backup will do?

On bitcoin-qt you should backup every 50 [send] transactions or so and you must backup every 90 [send] transactions or so.

Really? I thought once you have a backup from any period itwould be ok asit would auto update once used if you lose othe dat file or change machines.

[DannyHamilton]

Should we always have a recent backup all the time or and old backup will do?

On bitcoin-qt you should backup every 50 [send] transactions or so and you must backup every 90 [send] transactions or so.

Really?

Yes, really.

I thought once you have a backup from any period itwould be ok asit would auto update once used if you lose othe dat file or change machines.

You thought incorrectly.

[BurtW]

Should we always have a recent backup all the time or and old backup will do?

On bitcoin-qt you should backup every 50 [send] transactions or so and you must backup every 90 [send] transactions or so.

Note that this answer is specifically with respect to the bitcoin-qt wallet.  Other wallets have other backup requirements.

One of the reasons I really like the Trezor, Wallet32 and other deterministic wallets is that they do not require ongoing backups.  If you simply backup the seed for the deterministic wallet then you are done.  If you lose the Trezor (hardware wallet), your phone (Wallet32), or any deterministic wallet then all you need to do to recover all of your receiving addresses, change addresses and transactions is to enter the seed into another (compatible) deterministic wallet.

I now do all of my Bitcoin business with deterministic wallets because of this and have moved away from the other wallets.

PLUS a well designed deterministic wallet helps people avoid address reuse, which is good for Bitcoin, privacy and fungibility.

[Dabs]

On another extreme, you could make a back up every time you do a transaction. I think it might be easier to just have a daily or weekly automated backup.

On my accountant's computers, I have a script that runs every noon time (during their lunch break) that archives the files that have changed in the past week, every day. That data is usually a few megabytes every day, so it will be several months before the 500 gigabyte hard drive gets filled up with redundant backup data.

Then I can simply delete the oldest ones.

BurtW, are you aware of which deterministic wallets use compressed keys? (Armory is not yet using them.)