Partitions; Volumes - HP StoreEasy 1000 Administrator's Manual

Through the use of basic disks, you can create primary partitions or extended partitions. Partitions
can only encompass one LUN. Through the use of dynamic disks, you can create volumes that
span multiple LUNs. You can use the Windows Disk Management utility to convert basic disks
to dynamic disks or dynamic disks to basic disks and to manage the volumes residing on dynamic
disks. Other options include the ability to delete, extend, mirror, and repair these elements.

Partitions

Partitions exist as either primary partitions or extended partitions. The master boot record (MBR)
disk partitioning style supports volumes up to 2 terabytes in size and up to 4 primary partitions
per disk (or three primary partitions, one extended partition, and unlimited logical drives). Extended
partitions allow the user to create multiple logical drives. These partitions or logical disks can be
assigned drive letters or be used as mount points on existing disks. If mount points are used, it
should be noted that Services for UNIX (SFU) does not support mount points at this time. The
use of mount points in conjunction with NFS shares is not supported.
The GUID partition table (GPT) disk partitioning style supports volumes up to 18 exabytes in size
and up to 128 partitions per disk. Unlike MBR partitioned disks, data critical to platform operation
is located in partitions instead of unpartitioned or hidden sectors. In addition, GPT partitioned
disks have redundant primary and backup partition tables for improved partition data structure
integrity.
On the Volumes tab in the disk properties dialog box in Disk Management, disks with the GPT
partitioning style are displayed as GUID Partition Table (GPT) disks, and disks with the MBR
partitioning style are displayed as Master Boot Record (MBR) disks.

Volumes

When planning volumes, you must consider the limitations of the file system that you choose for
formatting the volumes. The default file system for Windows 2012 R2 is NTFS.
The operating system supports FAT32, FAT, NTFS, and Resilient File System (ReFS). All file
system types can be used on the HPE StoreEasy 1000 Storage system. However, VSS can only
use volumes that are NTFS formatted. Also, quota management is possible only on NTFS.
NTFS enables you to create an NTFS volume up to 16 TB using the default cluster size (4KB)
for large volumes. You can create NTFS volumes up to 256 TB using the maximum cluster size
of 64 KB. The formula for the maximum NTFS volume size is ([2 ^32 * cluster size] —64KB) for
Windows 2012 R2. Starting Windows 2012, Microsoft introduced ReFS which works well with
large data sets without performance impact. ReFS is not only designed to support volume sizes
of 2^64 bytes (allowed by Windows stack addresses), but it also supports larger volume sizes
of up to 2^78 bytes using 16 KB cluster sizes. This format also supports 2^64-1 byte file sizes,
2^64 files in a directory, and the same number of directories in a volume. For more information
on ReFS, see https://technet.microsoft.com/en-us/library/hh831724.aspx.
The RAID level of the LUNs included in a volume must be considered. All of the units that make
up a volume should have the same high-availability characteristics. In other words, the units
should all be of the same RAID level. For example, it would not be a good practice to include
both a RAID 1+0 and a RAID 5 array in the same volume set. By keeping all the units the same,
the entire volume retains the same performance and high-availability characteristics, making
managing and maintaining the volume much easier. If a dynamic disk goes offline, the entire
volume dependent on the one or more dynamic disks is unavailable. There could be a potential
for data loss depending on the nature of the failed LUN.
Volumes are created out of the dynamic disks, and can be expanded on the fly to extend over
multiple dynamic disks if they are spanned volumes. However, after a type of volume is selected,
it cannot be altered. For example, a spanning volume cannot be altered to a mirrored volume
without deleting and recreating the volume, unless it is a simple volume. Simple volumes can be
mirrored or converted to spanned volumes. Fault-tolerant disks cannot be extended. Therefore,
selection of the volume type is important. The same performance characteristics on numbers of
Storage management elements 119