Moving files on server / NFS mounts using Dolphin - How does this happen?

[oshunluvr]

I have a server I use for media storage. I am connected to it via NFS shares. The share is a single mount on the desktop, but a group of three mounts on the server connected via bind mounts. I was moving some files using Dolphin drag-and-drop and a question popped into my head:

Are the files moving through the network from the server to my desktop and back to the server?

It occurred to me this might be happening. Assuming yes - other than ssh and manually entering the mv command - is there a way to move files about on the server without sending them over the network? The server is headless and will remain that way so Remote Desktop is not and option (but an obvious solution). I am mostly just curious, but it also introduces an unnecessary point-of-failure for the transfer operation and an increase in the time it takes to complete such operations.

What to you big-time sysadmins do?

[DoYouKubuntu]

Re: Moving files on server / NFS mounts using Dolphin - How does this happen?

OL, let me state right off that I have no clue what you're talking about. Bind mount? WTF is that?! (I don't mind admitting that I'm [way] out of the loop!) However, here's my common sense take on your question.

I have a server I use for media storage. I am connected to it via NFS shares. The share is a single mount on the desktop, but a group of three mounts on the server connected via bind mounts. I was moving some files using Dolphin drag-and-drop and a question popped into my head:

Are the files moving through the network from the server to my desktop and back to the server?

Why would they? Picturing Dolphin in split view, 2 panes, the one on the left displaying the source directory and the one on the right the target directory, both on the server, why would dragging a file from the source to the target involve anything but those two directories?

It occurred to me this might be happening. Assuming yes - other than ssh and manually entering the mv command - is there a way to move files about on the server without sending them over the network?

Why would you need SSH? If the server's share(s) are mounted, just cd to the directory you want and mv the files.

Again, let me reiterate that I'm so far out of the loop (not working since 2003, combined with having brain surgery, have put quite a damper on my keeping up with things I don't need to know about) I truly have no idea what you're referring to, so I'm only thinking in terms of my own use of networked computers and accessing their drives from a prompt and/or Dolphin.

[sithlord48]

Re: Moving files on server / NFS mounts using Dolphin - How does this happen?

i have often wondered that myself.

Why would they? Picturing Dolphin in split view, 2 panes, the one on the left displaying the source directory and the one on the right the target directory, both on the server, why would dragging a file from the source to the target involve anything but those two directories?

it wouldn't but the data must be traveling thru the client,how else can you get a progress dialog on the client?

how does the local machine know to tell the server to move the files. as far as the client knows it's moving a file from folder A to folder B, where they are i dont' think matters. unless NFS-server is checking that its exports are copying one to another and then translates it to a simple cp command.

[SteveRiley]

Re: Moving files on server / NFS mounts using Dolphin - How does this happen?

The server is headless and will remain that way so Remote Desktop is not and option (but an obvious solution).

Perhaps my Windows background is now showing, but why is remote desktop not an option for headless servers? I've frequently used RD-type tools to manage headless servers in data centers far, far away.

Does NFS have some kind of remote-execution feature? If not, then using Dolphin, or any other client running on the local PC, to move files around on a remote server will cause the file to transfer from the server through the client and back to the server. To avoid that, you have to initiate the remote command on the server somehow.

[sithlord48]

Re: Moving files on server / NFS mounts using Dolphin - How does this happen?

headless, install NX-server you can start X on clients., you will need to install a desktop enviroment, but it(or X11) do not need to be running , my server boots to a CLI and its only GUI is thru NX, its never started on a local boot. i had to edit one setting to get it to not start X can't remember off the top of myhead but it was ez to find in a quick search .

[oshunluvr]

Re: Moving files on server / NFS mounts using Dolphin - How does this happen?

Actually, Steve brings up a good point - What I should have said was "Server with no desktop." Headless (without monitor, keyboard, mouse) isn't relative to the issue.

@DYK: The reason I asked is because to me - the common sense answer is the data does flow through the network to the client computer because that is the computer making the transfer request and as far as it "knows" the NFS shares are treated no differently from locally mounted partitions (IMO, this is one of the strengths of NFS).

I only brought up the bind mounts in the interest of full disclosure as my setup is a bit non-standard. If anyone is interested it's covered here.

The server itself is rather low-powered (Atom processor) so I keep all non-essential stuff off of it - like a desktop.

So it appears my best option is installing neatx or freeNX,. Thanks for the suggestion sithlord, I'll check into it.

[DoYouKubuntu]

Re: Moving files on server / NFS mounts using Dolphin - How does this happen?

@DYK: The reason I asked is because to me - the common sense answer is the data does flow through the network to the client computer because that is the computer making the transfer request and as far as it "knows" the NFS shares are treated no differently from locally mounted partitions (IMO, this is one of the strengths of NFS).

It's funny, because I'm seeing it exactly opposite--but with your same exact reasoning. To me, because shares are treated no differently from local drives, it makes sense that when their files are moved [from one location on the share to another on the share], it's just like physically sitting in front of that box and typing in the commands. Like I've said, I KNOW I'm out of the loop, and that's okay! I'd actually like to learn more about this issue just for the hell of it.

[SteveRiley]

Re: Moving files on server / NFS mounts using Dolphin - How does this happen?

Easy way to test:

1. Create a 10 GB file on ShareA.
2. From your client PC, transfer that file to ShareB.
3. Observe the behavior.

If you see that file flow through the network connection on your client PC, then you know that the command isn't running remotely. This will also take some time, of course, so that'll be another clue.

[DoYouKubuntu]

Re: Moving files on server / NFS mounts using Dolphin - How does this happen?

1. Create a 10 GB file on ShareA.
2. From your client PC, transfer that file to ShareB.
3. Observe the behavior.

Steve, in your example are ShareA and ShareB referring to two locations on the same share (computerA/directoryA and computerA/directoryB), or two different shares (computerA/directoryX and computerB/directoryY)? I'm not sure it matters in the scenario we're discussing, but I'm just wondering. In the OP, I'm pretty sure oshun was referring to two directories on the same share.

[oshunluvr]

Re: Moving files on server / NFS mounts using Dolphin - How does this happen?

Clearly, the files are moving through the network.Up/Down network indicators so that much. Next test will be time cost to do so.

[SteveRiley]

Re: Moving files on server / NFS mounts using Dolphin - How does this happen?

Steve, in your example are ShareA and ShareB referring to two locations on the same share (computerA/directoryA and computerA/directoryB), or two different shares (computerA/directoryX and computerB/directoryY)? I'm not sure it matters in the scenario we're discussing, but I'm just wondering. In the OP, I'm pretty sure oshun was referring to two directories on the same share.

It doesn't matter. Dolphin and mv and cp aren't smart enough to know the difference. To avoid transferring the data through the local client, you have to initiate the command on the remote server. You can do this with VNC, remote X, rexec, SSH...basically any tool that allows you to initiate the session from the server.

[kubicle]

Re: Moving files on server / NFS mounts using Dolphin - How does this happen?

Steve, in your example are ShareA and ShareB referring to two locations on the same share (computerA/directoryA and computerA/directoryB), or two different shares (computerA/directoryX and computerB/directoryY)? I'm not sure it matters in the scenario we're discussing, but I'm just wondering. In the OP, I'm pretty sure oshun was referring to two directories on the same share.

It doesn't matter. Dolphin and mv and cp aren't smart enough to know the difference. To avoid transferring the data through the local client, you have to initiate the command on the remote server. You can do this with VNC, remote X, rexec, SSH...basically any tool that allows you to initiate the session from the server.

If you're moving files within a single filesystem on a remote host (or local host) the data on disk doesn't actually (physically) "move" anywhere, it's just a bookkeeping operation (the data is changed to belong to another directory)...that's why moving files within a filesystem is (lightning) fast.

Things are more complicated if you're moving between two filesystems on a remote host or two remote hosts (that might not even be connected to each other directly)

[oshunluvr]

Re: Moving files on server / NFS mounts using Dolphin - How does this happen?

Ok, my test was a 33.8GB file copied using "time cp" in a terminal. I did it this way to avoid overhead from Dolphin getting in the mix.

I ssh'd to the server and copied from primary mount-to-mount (not from the bind mounts, although I doubt that has much of an impact) and then copied it again using cp in a terminal from the client computer.

no network - 10:08.50
networked - 20:50.57

Wow! Double the amount of time and I have a gigabit networked and my server and desktop are both using port aggregation.

Obviously, this was not a simple book-keeping move. That would only take milliseconds.

[SteveRiley]

Re: Moving files on server / NFS mounts using Dolphin - How does this happen?

If I'm interpreting your explanation correctly...
[*]In your first test you were ssh'ed into the server. When you ran the cp command, the command ran on that server. So the transfer stayed within the server.
[*]If your second test, you ran the cp command from your local client. This caused the file to transfer from the server, through your client, and back to the server. This took double the amount of time, which would be expected.

[oshunluvr]

Re: Moving files on server / NFS mounts using Dolphin - How does this happen?

Yeah Steve, you got it. So I suppose then a temp file is created on the client, thus the doubling of time?