The following taken from : Microsoft SQL Server 2016 Nutanix Best Practices Drive configuration: For optimal performance several virtual disks should be used. Nutanix suggest eight disks per SQL Server virtual machine spread across 4 SCSI controllers as laid out below: Drive Controller Type Controller # OS LSI SAS 0 SQL Sever installation LSI SAS 0 Backup LSI SAS 0 SQL Datafiles 1 PVSCSI 1 SQL Datafiles 2 PVSCSI 1 TempDB Datafiles 1 PVSCSI 2 TempDB Datafiles 2 PVSCSI 2 TempDB Log Files PVSCSI 3 Database Log Files PVSCSI 3 Cluster size formatting of all drives as below: SQL Data and log files - 64KB NTFS OS and SQL Server installation - 4KB NTFS - Server Team ?? ...
Prior Oracle Database 12c, an ASM instance ran on every node in the cluster and ASM Cluster File System (ACFS) Service on a node connected to the local ASM instance running on the same host to fetch the required metadata. If the ASM instance on a node were to fail, then ACFS file systems could no longer be accessed on that node. With introduction of Flex ASM in Oracle 12c, hard dependency between ASM and its clients has been relaxed and only a smaller number of ASM instances need run on a subset of servers in a cluster. In such a scenario, in order to make ACFS services available on nodes without an ASM instance, a new instance type has been introduced by Flex ASM: the ASM-proxy instance which works on behalf of a real ASM instance. ASM Proxy instance fetches the metadata about ACFS volumes and file systems from an ASM instance and caches it. If ASM instance is not available locally, ASM proxy instance connects to other ASM instances over the network to fetch the me...
When a transaction is being committed, each step is written into the transaction log. Each value that is being inserted, updated, or deleted is recorded so that if there is a failure before the log is written to the data file, the appropriate rollback or roll forward can take place. The transaction may take and release locks on tables or indexes. To view the entries in the log there is an undocumented fn_dblog command . The SQL Server transaction log contains the history of every action that modified anything in the database. Reading the log is often the last resort when investigating how certain changes occurred. It is one of the main forensic tools at your disposal when trying to identify the author of an unwanted change. Understanding the log and digging through it for information is pretty hard core and definitely not for the faint of heart. And the fact that the output of ::fn_dblog can easily go into millions of rows does not help either. But I’ll try to giv...
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