I wound up making use of SteelEye's Data Replication and also High Availability collection. They have variation fro Windows and also Linux (which had not been a need). The Data Replication protion permitted block degree replication (Synchronous or Asynchronous). The High Availability section permitted solutions to be switched from as soon as web server to an additional.
I've made use of 2.
DoubleTake is an usual one for applications that do not have much disaster recovery capacities constructed in.
Veritas Volume Replicator is an actually glossy venture - top quality one. I've seen that made use of with Microsoft Exchange, as an example, to reproduce information in between 2 various SANs.
If I needed to advise one over the various other, it would certainly be Veritas.
One point to take into consideration is just what you are shielding versus .
If you are shielding versus information corruption or unintended documents removal, you do not desire a continual - sync remedy, as the corruption/deletions will certainly be reproduced to the back-up prior to you can gain from it.
If on the various other hand you are intending to attain 100% uptime on your internet ranch while restarting among the web servers - synching every hr might not suffice.
VVR is an alternative. I've additionally made remedies where the essential information remains on a SAN and also can merely be remounted on a various web server if the web server drops.
As constantly, it relies on the application and also your needs for RTO/RPO.
I implement this by running Windows in a Xen VM under Linux (CentOS) and also making use of DRBD to mirror the VM's disk photos. Okay, so it's an added degree to identify, yet it is free and also offers you the adaptability to start including more VMs to your equipment. I additionally make use of Linux LVM to make conveniently resizeable disk quantities to make use of as VM disks. Equipment sensible, apart from 2 equipments there's not actually anything else essential, although an added network card per equipment committed to DRBD is constantly convenient.
We make use of MirrorFolder for this. It's documents degree, yet it's budget friendly ($ 40) and also very easy to set up and also make use of. We utilize it on web server doing website to website backups of concerning 250GB. It takes care of differentials and also offers you logs of progression. All the best!
There are numerous alternatives.
DFS-R is constructed right into Windows 2003 R2 and also 2008 (and also I utilize it). FRS is constructed right into 2000 and also 2003 R1, yet I would not advise it.
These are actually focused on documents shares and also are file-level mirrors, not block-level.
If you have a disk that you desire 2 web servers to see, after that you require windows clustering, yet you require an equipment base for that - either a self-supporting RAID array (as an example Dell MD3000) or SAN.
If you require to do this block-level, after that you're considering equipment remedies from SAN carriers - I've made use of Dell EqualLogic, yet there are loads in the marketplace, right approximately the linkes of EMC.
If you're attempting to mirror something like an Exchange web server for backup, after that a backup system that incorporates with Windows Shadow Copy would certainly be the appropriate strategy. I recognize that BackupExec (currently component of Symantec) have among these.