InfoScale™ 9.0 Solutions Guide - Linux
- Section I. Introducing Veritas InfoScale
- Section II. Solutions for Veritas InfoScale products
- Solutions for Veritas InfoScale products
- Solutions for Veritas InfoScale products
- Section III. Stack-level migration to IPv6 or dual stack
- Section IV. Improving database performance
- Overview of database accelerators
- Improving database performance with Veritas Concurrent I/O
- Improving database performance with atomic write I/O
- Section V. Using point-in-time copies
- Understanding point-in-time copy methods
- Backing up and recovering
- Preserving multiple point-in-time copies
- Online database backups
- Backing up on an off-host cluster file system
- Database recovery using Storage Checkpoints
- Backing up and recovering in a NetBackup environment
- Off-host processing
- Creating and refreshing test environments
- Creating point-in-time copies of files
- Section VI. Maximizing storage utilization
- Optimizing storage tiering with SmartTier
- Optimizing storage with Flexible Storage Sharing
- Optimizing storage tiering with SmartTier
- Section VII. Migrating data
- Understanding data migration
- Offline migration from LVM to VxVM
- Offline conversion of native file system to VxFS
- Online migration of a native file system to the VxFS file system
- Migrating a source file system to the VxFS file system over NFS v4
- VxFS features not available during online migration
- Migrating storage arrays
- Migrating data between platforms
- Overview of the Cross-Platform Data Sharing (CDS) feature
- CDS disk format and disk groups
- Setting up your system to use Cross-platform Data Sharing (CDS)
- Maintaining your system
- Disk tasks
- Disk group tasks
- Displaying information
- File system considerations
- Specifying the migration target
- Using the fscdsadm command
- Maintaining the list of target operating systems
- Migrating a file system on an ongoing basis
- Converting the byte order of a file system
- Migrating from Oracle ASM to Veritas File System
- Section VIII. Veritas InfoScale 4K sector device support solution
- Section IX. REST API support
- Support for configurations and operations using REST APIs
- Support for configurations and operations using REST APIs
- Section X. Reference
Restrictions on atomic write I/O functionality
This section describes the limitations of the atomic write I/O feature.
When atomic write I/O support is configured for VxVM raw volumes, the following limitations apply:
This functionality is not supported in CVM, FSS, VVR, or SmartIO environment.
Atomic write I/O is supported on concatenated volume layouts only.
Write I/O spanning across the atomic write I/O boundary is not supported.
Vector atomic write I/O is not supported.
Snapshot and mirroring of atomic write capable volume is not supported.
When atomic write I/O support is configured for VxFS file systems, the above limitations apply along with the following additional limitations:
FileSnap is not supported on an atomic capable volume.
Vector atomic write I/O is not supported.
Atomic writes are not supported on writeable clones. Promotion of writeable clones to primary is not supported when the file system resides on an atomic write enabled volume.
The "contig" option to setext is not honored. Similarly, extent size and reservation sizes that are not a multiple of the atomic write size are not honored.
dd copy of a file-system from a non-atomic capable volume to an atomic-capable volume is not supported.
Writes will return the error code ENOTSUP in the following cases:
The starting file offset is not aligned to a 512-byte boundary.
The ending file offset is not aligned to a 512-byte boundary, or the length is not a multiple of 512 bytes.
The memory buffer does not start on a 512-byte boundary.
The I/O straddles an atomic write (typically 16K) boundary. To determine the atomic write size, use the following command:
# vxprint -g diskgroup -m volume
An example of an atomic write that straddles a 16K boundary is one with offset 15K and length 2K.
The length exceeds the atomic write size typically 16K.