registry compression

[xpgeek]

Using registry first aid platinum, been using it for years, best there is, and kinda bored tonight so was looking at the new features added in 5.0 that I've never used before;

Registry Compression, a good idea ?

I'm thinking, doesn't a compressed file take longer to access then an un-compressed one? Is it just for saving some space, which I don't care about at all, or does it make it faster too?

The help file says the following :

"After a short while of deleting, adding and updating the registry data, the data becomes fragmented, with data and free space intermingled. This makes registry access slow. Registry First Aid allows you to defragment the registry with ease.

The option Defragment the Registry is available on the home page of Registry First Aid. It starts the registry analyzing to detect which registry files need to be defragmented and can be compressed. Finally it shows original registry sizes, size after compression, saved bytes and compression ratio."

But, there is no option to defragment and remove the empty space without also compressing it, so, registry compression, any speed improvement or just space saving ?

[Micron]

I wouldn't reccommend compressing the registry, or using a tool to do it for you. Its the same for partitioning the main (c:) Hard drive, you will get performance issues.

If you want to compress the registry manually, this is how it's done:

Backup the registry and be prepared to get back to where you started if things go wrong.

Update the %systemroot\repair directory using the command

rdisk /s-

rdisk will update repair data including the default, software and system hives. The repair version of the hives is compressed and reorganized. It is not an image copy. Adding the /s parameter gets the sam and security hives. The dash, -, instructs rdisk to not make a floppy disk copy.

Expand the registry hives to a temporary location:

expand %systemroot%\repair\default._ C:\temp\reg\default
expand %systemroot%\repair\sam._ C:\temp\reg\sam
expand %systemroot%\repair\security._ C:\temp\reg\security
expand %systemroot%\repair\software._ C:\temp\reg\software
expand %systemroot%\repair\system._ C:\temp\reg\system

A comparison of the files sizes in %temp% and %systemroot%\system32\config can reveal significant differences in size. If the sizes are close, the hive in question did not have much lost space to recover. Usually the software hive has the greatest space recovery.

Replace the version in %systemroot%\system32\config with the newly reindexed version in %temp%. NT keeps the hives open and locked. You can not simply copy the new version over the old versions. To get around this problem, you need to make the copy when NT is not loaded. For a FAT-based installation, bootup using DOS and make the copy using the DOS COPY command. For NTFS-based installations, I recommend using a recovery or backdoor copy of NT. Install NT on the PC in a different directory. Boot under the secondary NT and copy the hives for the inactive primary NT installation.

There is some risk in this procedure. But as the hives get large with a high amount of dead space, performance suffers. If your server or workstations gets slower and slower for no apparent reason, you may get the performance back using this approach.

Warning: Do not attempt if you are not in a position to recover back to the starting point.

[xpgeek]

Thank you for the reply. I've also now come to understand that the context in which they use the word compression is not what I had first thought it to mean. Usually when I think of compression, I think of a highly compressed file in size that then needs to be uncompressed on the fly to be used, but the context of the word in which they use it here is size of the registry section after defragmenting, so its not really compressing it beyond just making it smaller overall.