Veritas NetBackup™ Appliance Capacity Planning and Performance Tuning Guide
- About this Guide
- Section I. Capacity planning
- Analyzing your backup requirements
- Designing your backup system
- Section II. Best Practices
- Section III. Performance tuning
- Section IV. Quick reference to Capacity planning and Performance tuning
- Index
Deduplication disk I/O and RAID level settings
On the traditional storage array deduplication disk I/O and RAID level are bases for the performance measurement. With the NetBackup MSDP technology, as with vast majority of other deduplication technology currently on the market, deduplication disk I/O loses its primary performance measurement status. This being said, deduplication disk I/O still plays important part in the overall system performance, and should not be disregarded.
The following guidelines can help improve the deduplication disk I/O and RAID level settings:
NetBackup 52xx appliance deduplication disk I/O comes under pressure during rehydration of the backup images stored in the MSDP or the AdvancedDisk backup/restore operations. These operations are heavily dependent on the deduplication disk I/O throughput.
A traditional hard disk by its nature is very slow, mechanical devices cannot support concurrent I/O operations effectively. Storage array LUN's consisting of RAID groups are good in distributing load across a number of hard disks and thus improving disk storage I/O performance.
RAID protocols have their own limitations and RAID 6 and RAID 5 have a disadvantage of slower performance during I/O write operations than RAID 1
To further optimize the performance of the storage pool and avoid oversaturation, two key adjustments are recommended to the:
'Maximum I/O Streams' count configuration of the storage pool. For the NetBackup 52xx appliance-based storage pools, Veritas recommends up to an optimal value of 98 streams per pool.
'Maximum concurrent jobs' value for each of the storage units that each media server uses to push data to the shared target storage pool.
Note:
Deduplication disk I/O throughput depends on the appliance storage configuration with the general rule of more disks meaning better performance. NetBackup 52xx appliance with 4TB storage configuration has a significantly lower deduplication disk I/O than a 24TB or better storage configurations. This is a general rule of thumb for any storage array and disk type, increased number of spindles provides better throughput at high disk I/O, especially when the number of streams is high.