Earlier we wrote about scalable Zimbra Collaboration Suite Open-Source Edition. Adding new mail repositories can be done without stopping the infrastructure on which Zimbra is deployed. This feature is highly valued by SaaS providers who provide their customers with access to the Zimbra Collaboration Suite on a commercial basis. However, this scaling process is not without a number of disadvantages. The fact is that when creating a new account in the free version of Zimbra, it turns out to be rigidly linked to the mail storage on which it was created, and transferring it to another server using the built-in Zimbra OSE tools turns out to be an unsafe and rather laborious process. However, mailbox migrations don't always involve scale-out. For example, SaaS providers can use account transfers to more productive servers in cases where their customers change their tariff plan. Also, the transfer of accounts may be necessary for large organizations during restructuring.
A powerful tool for transferring mail accounts between servers is Zextras PowerStore, which is part of a set of modular extensions . Thanks to the team doMailboxMove, this extension allows you to quickly and conveniently transfer not only individual accounts, but also entire domains to other mail storages. Let's see how it works and in what cases its application will give the maximum effect.
For example, consider a company that started out as a small office space but has grown to a mid-sized enterprise with a few hundred employees. At the very beginning, the Zimbra Collaboration Suite Open-Source Edition was implemented at the enterprise. The free and fairly low-hardware collaboration solution is perfect for a start-up company. However, after the number of employees in the enterprise multiplied, the server stopped coping with the load and began to work more slowly. In order to solve this problem, the management allocated money for the purchase of a new mail storage in order to place part of the accounts on it. However, in itself, the connection of the second storage did not give anything, because all the created accounts remained on the old server, which simply could not cope with their number.
Zimbra Collaboration Suite is designed so that the main role in its performance is played by the speed of reading and writing media, and therefore increasing the computing power of the server will not double the performance of Zimbra. In other words, two servers with 4-core processors and 32 gigabytes of RAM will perform much better than one server with an 8-core processor and 64 gigabytes of RAM.
In order to resolve this issue, the system administrator used the solution from Zextras. With a command like zxsuite powerstore doMailboxMove mail2.company.com accounts [email protected] stages data,account the administrator transfers the last hundred created accounts one by one to the new storage. After the completion of this process, the load on the old server was significantly reduced and work in Zimbra again became comfortable and enjoyable for users.
Imagine a different situation: a small company uses the services of a SaaS provider to access Zimbra on a multi-tenant basis. At the same time, the company has its own tariff, access to account administration, and so on. However, the company soon wins a major tender and dramatically increases its staff. At the same time, the role of the joint work system increases accordingly. The ability to use an address book, organize instant communication between employees, as well as coordinate actions using calendars and diaries is extremely important when implementing large projects. At the same time, in the face of time constraints, it is not possible to switch to Zimbra's own infrastructure. In this regard, the management decides to conclude a new contract with its SaaS provider, which will have a stricter SLA and, accordingly, a higher cost of services.
The SaaS provider, in turn, has several storages that are used to serve customers who have connected different tariff plans. In addition to SLA, servers for cheaper tariffs may be equipped with slower HDDs, be backed up relatively infrequently, and also not be able to synchronize account data with mobile devices. A major difference is also the period during which the SaaS provider stores customer data after the end of the subscription to its services. Therefore, after signing the contract, the system administrator of the SaaS provider needs to transfer the data of all enterprise accounts to a new, more fault-tolerant and productive mail storage, which will guarantee the client a high SLA.
It will take some time for the administrator to complete the mailbox migration, and it is quite difficult to predict how long the mailbox migration process will take. In order to meet the 15-minute technical break, the administrator decides to migrate mailboxes in two stages. As part of the first stage, he will copy all user data to the new server, and as part of the second stage, he will transfer the accounts themselves. To execute the first step he runs the command zxsuite powerstore doMailboxMove secureserver.saas.com domains company.ru stages data. Thanks to this, all account data from the company's domain will be securely transferred to a new secure server. They are copied incrementally, so when the accounts are finally transferred to the new server, only the data that appeared after the first copy will be copied. At the time of the technical break, the system administrator just needs to enter the command zxsuite powerstore doMailboxMove secureserver.saas.com domains company.ru stages data,account notifications [email protected]. Thanks to her, the process of transferring a domain to a new server will be completed completely. Also, immediately after the completion of this command, the administrator will receive a notification about its completion and it will be possible to inform the client about the successful transition to a more productive and reliable server.
However, do not forget that backup copies of the migrated mailboxes remain on the old server. The SaaS provider is not interested in keeping them on the old server and so the administrator decides to delete them. He does this with the command zxsuite powerstore doPurgeMailboxes ignore_retention true. Thanks to this command, all backup copies of mailboxes transferred to the new server will be instantly deleted from the old server.
Thus, as we were able to verify, Zextras PowerStore gives the Zimbra administrator almost unlimited options for managing mailboxes, allowing not only to achieve horizontal scaling, but even solve some business problems. Additionally, moving mailboxes between repositories can be used to improve the security of the Zimbra mail repositories update process, but this topic deserves a separate article.
Source: habr.com