Foreword Crash recovery is probably the most important capability of any good data archiving system. It is also the hardest to engineer. If you can make
good backups, and restore files occasionally, that's great, but when your system goes down, it is a tedious and time consuming process to re-install the operating system and configure it properly before you can restore
your data. Crash recovery eliminates the hard steps. RecoverEDGE
for Linux is, quite simply, the best engineered, best tested crash recovery system available. It has been under development and constant update since June of 1997. We shipped our first commercial release in April of 1999.
Since that time, other backup software vendors have rushed to market with products that claim to do Linux Crash Recovery, but in reality only contain a limited subset of the features contained within Recover
EDGE. Getting to market with a BASIC
crash recovery product is quite simple. You just create a product with an extremely limited feature set that can restore a base system from floppy disks and a tape. This works fine as long as;
- no special configuration has been done
- you only use base filesystem types
- no special filesystem parameters have been set
- you really are an
fdisk expert
you only need to operate locally.
Well, you can hack that much of a crash recovery tool together in just a few months, and it will probably be great for the Linux hobby marketplace. We specialize in the commercial Linux market place, where end
users may not know anything about Linux, and systems are far more complicated. Our minimum requirements before we ship a crash recovery system for ANY platform are:
- Complete discovery of all system resources, libraries, modules, etc. Automatically.
- Full low-level control of filesystems.
- Network and modem support included on crash recovery media with no prompting or special user knowledge required.
Over the next few minutes, you'll learn why you can't afford to trust anything else to protect your critical data. This document talks about many of the quirks and intricacies of Linux that make it very difficult
to create usable crash recovery media. If you get nothing else from these documents, remember that we've already looked into these issues and engineered our product in such a way that you don't have to worry about
them. We just take care of it for you. Basic Concepts Linux is unique among Unix variants. For the most part, on a Unix system the operating system (kernel) file is always the
same (/unix for example), the shared libraries all live in the same directory, and all files useful to crash recovery reside in fixed locations in the filesystem. There is also generally a single way to boot the
operating system. With Linux, everything is different. The kernel doesn't have to be /vmlinuzor /boot/vmlinuz, and the libraries
and utilities can be scattered all over the hard drive. There are even multiple ways to boot with LILO, or you may choose not to use LILO at all. We'll examine these issues and more, tell you what we do to solve
them, and tell you what to watch out for when evaluating other products. |
