HP VMA-series Memory Arrays VMA3205 & VMA3210 PCIe Direct-Connect Release Notes - December, 2012

5
VMA-series Memory Array: General Recommendations
The following are general recommendations for getting optimal performance with the HP VMA-series
memory arrays.
Alignment of data transfer I/O block sizes
The internal flash addressing of the VMA is based on 4K (4096) byte boundaries. Read or write
requests that do not begin on a 4KB aligned target block address or are of I/O sizes not a multiple of
4KB may suffer a performance impact. Write performance is more seriously affected by non-4KB
alignment. For example, if a user application writes 512 bytes starting at the last 256 bytes of a 4K
page, the result on hardware would be two 4K read-modify-write updates.
In order to achieve optimal throughput and performance with the VMA-series Memory Arrays, care
should be given to tuning the intended application, data layout structures on the array, and the
connected host server.
Data layout structure alignment on VMA:
The data layout structures created on the array storage by the logical volume manager and filesystem
on the host should be made so that they are 4KB aligned, meaning that partition sizes, LVM striping
and other data structures are 4KB aligned. Consider the following when creating data layout
structures on the VMA:
• Partition sizes are 4KB aligned
• Volume manager stripe sizes are multiple of 4KB
• Filesystem blocks are 4KB aligned
Tune application to issue I/Os which are multiple of 4KB
Most high level applications can be configured to issue certain I/O block sizes for increased
performance. Ensure that configured I/O block size and if appropriate the beginning block addresses
for I/Os are 4KB aligned.
Partition for parallelization of I/O for applications
The VMA when first discovered on the host server will initially appear as one big LUN (disk).
Partitioning of the VMA storage into multiple partitions may allow applications to launch multiple
threads for greater I/O parallelism & performance. Again use care to make sure partition sizes and
boundaries are 4KB aligned.
Data Backup
As with any data storage device, array or system, data stored should always be protected with a
regular data backup schedule that is appropriate for the criticalness of the data stored. You can use
the HP Data Protector software or your chosen backup software utility to backup your data on the
VMA as done with other standard rotational disk based storage systems.
CLI commands are case sensitive
All CLI commands are case sensitive and usually are all lower case. CLI commands are documented
in appendices of the user manuals.