High-priority users can be replicated while others are protected only by backups, resulting in lower replication costs.
These activities tend to be ad hoc, one-off uses that are encumbered by reservations. If the primary server experiences a hardware or software failure, the secondary server assumes its IP address and hostname and resumes operation.
Another advantage is lower pricing per mailbox than MailShadow.
At its core, it mirrors the capabilities of Akimbi Slingshot, setting up, deploying, copying, and tearing down complex multiserver configurations of virtual machines. For maximum protection, administrators might choose to implement a fail-over system plus the CDP that DigiVault provides. Booting the server personas from the network also eliminates the need for a local disk on most servers. In addition, LifeKeeper supports shared storage between the primary and secondary servers, which can speed up the fail-over process. Administrators can control replication by storage group, by Exchange server, or by individual accounts. All transactions are recorded as they occur, ensuring no loss of e-mails that have arrived since the last backup.
Transactions received since the last backup are backed up before the restore commences.
It enables sites to plan usage on their virtual servers. Pricing is per pair of servers, based on the server in the pair with the greater number of CPUs. The console and the DigiStore vault can share the same system. This is done asynchronously, but in the same sequence as on the primary server. Any changes to the mailboxes that occur during the fail-over are incrementally updated on the primary server.
Which is least expensive will depend on how many users per server you have.
Although the repository is compressed, storage requirements will quickly mount if you keep each version of messages in the store. Zoho is definitely the standout in the group. Administrators can control replication by storage group, by Exchange server, or by individual accounts.
I had to go with Zoho. This ensures that the proper interface exists on the proper network with the proper IP information. Each server came up, the UI automatically updated with the status of the servers, and after a normal boot time, the application was available. All but Neverfail can protect multiple Exchange servers with one backup server, Neverfail requiring one backup server for each Exchange server protected. This reservation system is a key distinguishing feature of VQMS; Akimbi Slingshot has no equivalent.
Users connecting via MAPI or the Outlook Web Access client may need to restart the client to connect to the backup server. The traditional backup-and-restore process can take hours to resurrect a server, and any mail that comes in while the server is down will be lost. Akimbi does not have this feature.
If a primary Exchange server fails, or its database is corrupted, the designated accounts can access the backup server instead.
This, too, I would recommend.