Networking – Where does the process occur when zipping a file on a network mapped drive

networkingzip

I want to copy a number of large files that will compress well from a mapped drive to my local hard drive. Will zipping the files make the overall processing time shorter?

What I am thinking is, can the zip program zip the files on the mapped drive or does it need to pull the files to memory (that is locally) to zip them? This will result in the files being copied across the network 3 times – once to get the raw file to zip, once to put the zipped file back on the mapped drive, and the once to copy the zipped file back again. If this is the case am I better off just copying the files across uncompressed?

My other option is to remote into a server which is geographically close to the drive I am mapping, and zip it from there, then come back to my local pc and copy the zipped files.

Best Answer

Any program that creates a ZIP file is basically reads some files and writes out a ZIP file. So, if you're zipping files that are located on a remote computer, these files will have to be read over the network, uncompressed. The ZIP program will write the ZIP file locally, so no further network activity will occur. But in terms of network traffic, it is no different than first copying the files to a local disk and zipping them afterwards.

This is true regardless of what program you use to create a ZIP archive.

If you can remote into that server and compress the files there, and copy the already-zipped files, then you'll save some network traffic if the files can be compressed effectively (e.g. some files do not compress well, like most video files, encrypted files, etc.).

If your network is not 100% reliable, and your data transfer will take considerable time, it is better to copy uncompressed files first, and ZIP them later, and not ZIP the files directly over the network. If some network error occurs while zipping, you'll have to start the process from the beginning. And there are file copy programs that can re-start aborted/failed copy without re-transmitting already copied data.

Related Solutions

File name: ‘winmail.dat’ Virus name: ‘ExceedinglyInfected’

While it is not impossible that some malicious program is actually including a virus in your outgoing mail, the other likelihood is that your corporate network has a mail filter that prevents certain types of attachments. winmail.dat is basically Microsoft Outlook's catch-all container format for rich text and, I think, OLE objects (such as attachments). It might be detecting the ZIP file within the OLE container and blocking it. This is standard practice for corporate networks in many environments containing proprietary or sensitive data.

You could try these instructions from Microsoft to alleviate the issue, but since you said you are using the web client (Outlook Web Access?) the instructions might not be applicable to you.

Unzip file on small drive

Sane(-oid) Method

If you had a big enough flash drive (or writable network location, like another CIFS-capable computer on the network), you could extract one file at a time from the archive, then delete the file from the archive, using the (~20GB free) "other space" as the temporary/scratch location. Every archiving utility I've ever worked with can specify an alternate temporary location.

This example script uses 7-zip (as well as grep and sed):

@ECHO OFF
SETLOCAL

SET ARCHIVE=temp.zip
SET SCRATCH_PATH=D:\temp
SET DEST_DIR=%~dp0\extracted

FOR /F "delims=*" %%f IN ('7z.exe l "%ARCHIVE%" -slt ^| grep -B1 "Folder = -" ^| grep "Path = " ^| sed "s/Path = //"') DO (
    @ECHO.
    @ECHO %%~f
    7z.exe x -y -o"%DEST_DIR%" -w"%SCRATCH_DIR%" "%ARCHIVE%" "%%~f" >NUL
    7z.exe d -w"%SCRATCH_DIR%" "%ARCHIVE%" "%%~f" >NUL
    FOR %%g IN (%ARCHIVE%) DO @ECHO   %ARCHIVE%: %%~zg
)

It is functionally correct, though I did not attempt to create a file too big to extract on my computer just to test it.

Crazy Method

You could also temporarily compress some files on the hard drive that you know you won't need during the extraction process (like, say Office) to free up just enough space to extract the files, then reverse the process once extraction is complete.