Administrator Guide

• Virtually – All disk space is allocated into tiers. The fastest disks reside in Tier 1 and slower drives with lower performance reside in

Tier 3. Data that is accessed frequently remains in Tier 1, and data that has not been accessed for the last 12 progression cycles is

gradually migrated to Tiers 2 and 3. Data is promoted to a higher tier after three days of consistent activity. Disk tiering is shown when

you select a Storage Type.

For SCv3000, SC5020, and SC7020 storage systems, Storage Center uses the Automatic Drive Placement function to manage drives

automatically. When configuring a storage system, Storage Center manages the disks into folders based on function of the disk. FIPS-

certified Self-Encrypting Drives (SEDs) are managed into a separate folder than other disks. When Storage Center detects new disks, it

manages the disk into the appropriate folder.

In Storage Center version 7.3 and later, the Automatic Drive Placement function can be turned on or off for all Storage Centers (except

SCv2000 series storage systems) using the Storage Center Storage settings.

Disk Management on SCv2000 series Storage Systems

Storage Centers with SCv2000 series storage systems manage disks automatically, limiting the disk management options. After adding

disks, Storage Center recognizes the new disks, creates a new disk folder if necessary, then manages the disks in the disk folder. If a disk

is intentionally down for testing purposes, then is deleted, you can restore the disk to manage the disk again in a disk folder.

The following disk management options are not available for SCv2000 series storage systems:

• Creating disk folders

• Adding disks to disk folders

• Managing disk spares

Disk Folders

A disk folder contains both managed drives and spare disk space. Managed drives are used for data storage. Spare disk space is held in

reserve to automatically replace a drive if a drive fails. By default, the Assigned disk folder is the parent disk folder for all drives. Drives are

further grouped by class in subordinate folders.

Disk Classes

Disks are classified based on their performance characteristics. Each class is shown in a separate folder within the Assigned disk folder.

• Hard Disk Drives (HDDs) – For HDDs, the disk classification describes its spindle speed and can be any of three disk types.

• 7K (RPM)

• 10K (RPM)

• 15K (RPM)

• Solid State Drives (SSDs) – SSDs are differentiated by read or write optimization.

• Write-intensive (SLC SSD)

• Read-intensive (MLC SSD)

Drive Spares

Drive spares are drives or drive space reserved by the Storage Center to compensate for a failed drive. When a drive fails, Storage Center

restripes the data across the remaining drives.

Distributed Sparing

When updating to Storage Center version 7.3, a banner message prompts you to optimize disks. Clicking the link guides you through the

process of optimizing disks for Distributed Sparing. When disks are optimized, spare disk space is distributed across all drives in a drive

folder and is designated as Spare Space. This allows the system to use all disks in a balanced and optimized manner, and ensures the

fastest recovery time following a disk failure. Distributed Sparing is the default for systems shipping with Storage Center version 7.3.

Reserved Spare Drive

Prior to Storage Center version 7.3, a spare drive is used as a replacement for the failed drive. Storage Center designates at least one

drive spare for each disk class. Storage Center groups drives into groups of no more than 21 drives, with one drive in each group

designated as a spare drive. For example, a disk class containing 21 drives will have 20 managed drives and one spare drive. A disk class

with 22 drives will have 20 managed drives and two spare drives. Storage Center designates the one additional drive as a spare drive.

Storage Center designates the largest drives in the disk class as spare drives.

Storage Center Overview