Storage system requirements and reducing the risk of data corruption
You can use many types of storage for Tivoli® Storage Manager. If you use block disk storage, solid-state drives (SSD), or network-attached file systems for Tivoli Storage Manager server storage, ensure that the storage meets requirements.
Storage can be connected to the server system by any method that is valid for the operating system. For example, the storage can be attached directly, or by using Fibre Channel or iSCSI technology.
Because of the many storage systems that can meet the requirements for server storage, a list of such devices is not available. Contact the vendor if you have questions about whether a system meets Tivoli Storage Manager requirements.
For details about file system requirements, see technote 1902417. For details about network file system (NFS) requirements, see technote 1470193.
Storage and file systems must report write and commit results synchronously and accurately to the Tivoli Storage Manager server. Unreported or asynchronously reported write errors that result in data not being permanently committed to the storage system can cause data corruption. Data corruption can cause operational failures, including failure to start the server, and data recovery is typically required.
You can reduce the risk of data corruption with the following tips:
- Write cache
- Disk systems use write cache to improve system performance. To reduce the risk of data
corruption, the storage system must reliably commit the data in the write cache to permanent
storage.
The write cache typically has a battery to prevent loss of data from the cache during short power outages. For critical systems, consider backup power sources to protect the cache from extended power outages.
- Direct I/O
- Direct I/O meets the server's need for synchronous and accurate reporting on data write and
commit operations.Attention: Do not disable direct I/O in situations where the method of write caching has a potential to cause data loss. Disabling direct I/O can greatly increase the potential for data loss because more data is cached by the file system, in addition to the disk system.
- Storage replication
- Environments that replicate Tivoli Storage
Manager storage
must use features such as maintenance of write order between the source (local server) and the
target (remote server). The database, active log, archive logs, and storage pools must be part of a
consistency group. A consistency group maintains relationships among volumes to preserve write order
so that they can be recovered. Any I/O to the members of the target consistency group must be
written in the same order as the source and maintain the same volatility
characteristics.
To maintain synchronization between Tivoli Storage Manager servers at local and remote sites, do not start a server at the remote site except in a failover situation. Monitor for synchronization of data at the local and remote locations. If synchronization is lost, you must restore the server at the remote location by using Tivoli Storage Manager restore commands for the database and storage pools.