2. Planning a Storage Spaces deployment
Successful deployment requires careful planning to ensure
problems don’t arise during or after the deployment process. The
following issues should be considered when planning the deployment of
Storage Spaces for your organization:
-
Hardware
-
Performance
-
Resiliency
-
Availability
-
Management
-
Scalability
The hardware requirements for implementing Storage Spaces
define the kinds of physical storage devices and formats that can be
used for creating storage pools. These hardware requirements vary
depending on whether or not the Failover Clustering feature is being
used to provide high availability for your storage pools.
If you are deploying Storage Spaces without Failover
Clustering, the supported types of physical storage devices are as
follows:
-
Serial ATA (SATA) hard drives, including solid state
drives (SSDs)
-
Serial Attached SCSI (SAS) hard drives, including
SSDs
Note
USB drives and Storage Spaces
Although using USB 2.0 hard drives with Storage Spaces is
supported, it is not recommended because of the performance
limitations of using USB 2.0 to perform simultaneous reads and
writes to multiple, connected USB drives.
In addition, these devices can be connected to a server
running Windows Server 2012 in the following ways:
-
Internal connection using SATA or SAS controllers
-
External connection to a JBOD enclosure of SATA
disks
-
External connection to a SAS storage array
If you are deploying a highly available (HA) Storage Spaces
solution, the requirements are as follows:
-
Two servers running Windows Server 2012 with the Failover
Clustering feature installed and configured to use cluster
shared volumes (CSVs).
-
SAS-connected JBODs that comply with the Certified for
Windows Server 2012 logo requirements.
-
You cannot use iSCSI storage devices for an HA Storage
Spaces solution.
Note
Storage Spaces and hardware RAID
Storage Spaces cannot be used in conjunction with hardware
RAID. Choosing between hardware RAID and Storage Spaces depends on
several factors:
-
Choose Storage Spaces when you want to be able to
virtualize and deploy shared storage of data using thin
provisioning and save money by using low-cost, commodity hard
drives, while ensuring a level of resiliency similar to what
RAID can provide.
-
Choose a hardware RAID solution for a server when you
need to ensure data integrity, fault tolerance, and high
performance—for example, a RAID 5 or RAID 6 solution
implemented using a RAID controller card. You should also
choose hardware RAID when you want to ensure data integrity
and fault tolerance for a server’s boot volume—for example, by
configuring the boot volume as a RAID 1 or RAID 10
volume.
If a server has a RAID controller card and multiple hard
drives and you want to use Storage Spaces to pool together these
drives, you need to configure the RAID card to expose each drive
separately to the operating system.
Note
SES SAS
JBODs
SCSI Enclosure Services (SES) is a protocol that allows the
controller to send and receive diagnostic information to connected
storage devices. For example, a SAS JBOD enclosure that supports
SES has a series of LED lights on the enclosure, with each LED
corresponding to one of the SAS hard drives in the enclosure. When
Storage Spaces is implemented using SAS JBODs that support SES,
Storage Spaces can use SES to light up the LED of a drive that has
failed so that you can quickly determine which drive needs to be
replaced in the enclosure when Storage Spaces notifies that a
drive in a storage pool has failed.
Search the Windows Server Catalog at http://windowsservercatalog.com to find Certified
for Windows Server 2012 SAS JBODs that support the SES version 3
protocol. Then go to the vendor’s website and confirm that the
devices support SES.
To ensure optimal performance of Storage Spaces, make sure you
consider the following:
-
Use enterprise-level SAS disks if you can afford them to
get optimum performance from your Storage Spaces solution. Make
sure you also use top-quality SAS controller cards as well. Most
SAS controller cards are backward compatible for connecting to
SATA disks, so you can use these if your budget is limited. If
top performance is needed and money is no object, consider using
SSDs.
-
Create different storage pools for the different
performance needs of your environment, and populate the pools
with appropriate kinds of physical disks. For example, a storage
pool for a high-speed file server might contain a mix of SSDs
and 15,000-RPM SAS disks, while another storage pool used mainly
for archiving multimedia presentations could use cheaper
7200-RPM SATA disks.
Provisioning the right type of virtual disk from a storage
pool involves the following considerations:
-
For general-purpose file servers and similar uses, use
mirror virtual disks to ensure resiliency against the failure of
one or two physical disks in the pool.
-
For archival data and streaming media, use parity virtual
disks. Because of the higher overhead they require when
performing random I/O, do not use parity virtual disks for
general-purpose file servers.
-
For temporary storage such as scratch files for
data-editing applications, simple virtual disks can be
implemented.
Note
Resilient File System
You can gain additional resiliency by formatting volumes
using the new Resilient File System (ReFS) included in Windows
Server 2012. ReFS provides automatic data-integrity maintenance
and can be used to add an additional layer of resiliency above and
beyond what mirror or parity virtual disks can provide.
