Dell EMC VxFlex Ready Node, Руководство пользователя

Страница: 30 / 354

Figure 2 Protection Domains and Storage Pools
You must assign a media type setting to each Storage Pool. Supported types are:
HDD, SSD and Transitional (allows for migration flows).
If all SDSs in a Protection Domain have two physical drives associated with them—
one HDD, and the other SSD— you should define two Storage Pools:
l
Magnetic Storage Pool
Consists of all HDDs in the Protection Domain
l
High performance Storage Pool
Consists of all SSDs used for storage purposes in the Protection Domain
Note: Mixing different types of SSD's is not recommended and creating a
separate Storage Pool for each type is the recommended best practice. For
example: SAS SSD, SATA SSD, NVMe SAS SSD.
Note:
n
VxFlex OS might not perform optimally if there are large differences
between the sizes of the devices in the same Storage Pool. For example, if
one device has a much larger capacity than the rest of the devices,
performance may be affected. After adding devices, you can define how
much of the device capacity is available to VxFlex OS by using the SCLI
modify_sds_device_capacity
command.
Storage Pools support the following data layouts for HDD or SSD media:
l
Medium Granularity (MG): space allocation occurs at 1MB units
n
suppports HDD and SSD media
l
Fine Granularity (FG):
n
requires SSD media and NVDIMM for acceleration
n
space allocation occurs at 4KB units
n
includes persistent checksum for data integrity
n
supports data compression which reduces the size of data stored on the disk
n
supports thin-provisioned, zero-padded volumes
Note: FG and MG storage pools can both exist in a single SDS. You can also
migrate volumes across the two layouts.
Each Storage Pool can work in one of the following modes:
l
Zero-padding enabled
Ensures that every read from an area previously not written to returns zeros.
Some applications might depend on this behavior. Furthermore, zero padding
Architecture
30 Dell EMC VxFlex Ready Node AMS User Guide