Works like Volume Shadow Copy Service (VSS) for Windows. Windows administrators use VSS to take point in time snapshots, but before Hot Copy Linux administrators didn’t have an equivalent. We created Linux Hot Copy so every Linux server has a universal disk snapshot that is fast and easy to use.
Linux Hot Copy creates an instant point-in-time volume snapshot of any block device while the system is running without interrupting applications.
Unlike LVM, you don’t need dedicated Volume Group space to maintain the snapshot. Linux Hot Copy automatically uses free space on your block device for storage, enabling you to use it on any device. Or, specify an alternate device with more space to use as a changed block store.
Outperforms LVM snapshots. Linux Hot Copy has built-in file system awareness for Ext2/3/4 ReiserFS 3. It knows what parts of the block device are used by the file system and when you write to unused blocks on the disk it doesn’t perform a copy-on-write for these disk writes, enhancing performance.
Yes, you can read and even write to your snapshots. This opens up seemingly endless possibilities for use in system administration, allowing you to test scripts and programs on your data before running them on the live environment.
*Known Linux Kernels with Severely Broken Ext4
There was an issue with Ext4 introduced in "vanilla" Kernel.org kernel 2.6.32 and has been patched and released "down stream" into various Linux distributions. When any Ext4 file system snapshot is performed on an effected kernel the file system can deadlock causing a hung or crashed operating system.
This is a Linux kernel bug completely out of the control of Idera
Do not use the following Linux kernel versions with Ext4:
Ubuntu Lucid (10.04) Betas and Release Candidates - we have reports that Ubuntu Lucid 2.6.32-24.41 and greater are fixed
Ubuntu Maverick (10.10) Betas and Release Candidates
Debian 6 (Squeeze) Betas and Release Candidates
Fedora Core 12 Betas and Release Candidates
Xen (4.0 / 4.1) - Do Not use Ext4 on 2.6.32-5-xen - 2.6.32-35-xen_02
Kernel.org Bug Report
Ubuntu Bug Report