Thursday, April 29, 2010

Consultant Tools Series: 7-Zip

I like to think that I'm generally aware of new tools and technologies, but sometimes good technology slips by in areas where I'm not looking.

I've used WinZip for eons for situations where I have to e-mail files to people (yes, I even paid for a license!). And I have used WinRAR for years for larger files, like SQL Server backups and VHD backups. Between those two products, I thought I had the compression category pretty well covered.

Well, a few weeks ago I randomly stumbled across a reference to a free, open source compression software utility called 7-Zip. Apparently most of my friends and colleagues had heard of it, and one has been using it for quite a while.

Since I like WinZip's convenience and speed, and I'm a big fan of WinRAR's compression performance, I was skeptical that this free tool could compare with both WinZip and WinRAR, but I decided to give it a try.

I had a 1.67 gigabyte Outlook PST backup file, so I decided to start with that. Not only was 7zip faster, but it's native 7z compression was better than WinRAR.

7-Zip shrunk the file down to 443MB in 9 minutes 23 seconds, while WinRAR got down to 485MB in 10 minutes 45 seconds. Wow.

Impressed, I then tried a 29.2 gigabyte VHD file. WinRAR brought the file down to 10.4 gigabytes, while 7zip shrunk it to 8.9 gigabytes. Both took roughly two hours, so I didn't compare their actual times, but given the improved compression, I'd gladly use 7zip even if it took a few minutes longer.

I'm now a 7zip convert when it comes to compressing large files. I haven't yet tried unzipping my 7z files to ensure that they don't have any errors, but I'll gladly spend some time testing it if it will save me 10-15% space on my backup and archive disks.

The one obvious drawback to the 7z file format used by 7-Zip is that it isn't as well known or universally supported as the zip file format. However, I have noticed that a lot more people are now e-mailing RAR files out (and Microsoft is distributing VHDs in RAR format) without any problems or confusion, so maybe 7-Zip won't be such a leap for people. And since it is free, it's easy for anyone to download and use, and doesn't have any trialware nag windows to deal with.

The other observation I made is that using 7-Zip to create a zip file is slower and produces a zip file that is much larger than what WinZip creates (at least using whatever settings I used). So for now, it seems that WinZip still has a role.

Given the performance I've observed with the 7z format, I'm hoping it becomes widely adopted. Since it is free and open source, it would be nice to have on client's servers instead of the ubiquitous WinZip "Trial Mode - Purchase Now" message that I see constantly.

Give it a try and let me know what you think, or if you are already a 7-Zip user, let me know if you have found any other pros or cons.

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