Requirements for Dynamic Tiering
System requirements for provisioning
The system requirements for provisioning include basic hardware and licensing requirements as well as additional requirements for shared memory and cache management devices.
- The storage system hardware and firmware must be configured and ready for use.
- The parity groups in the storage system must be configured and ready for use.
- Hitachi Device Manager - Storage Navigator must be configured and ready for use. For details and instructions, see the System Administrator Guide for your storage system.
- The license keys for the provisioning software products must be enabled. For details and instructions, see the System Administrator Guide for your storage system.
- The required amount of shared memory for your operational environment must be installed in the storage system.
- The required number of cache management devices must be available.
- The desired system option modes (SOMs) must be enabled on your storage system before you begin operations. For information about SOMs, contact customer support.
License requirements
Before you use Dynamic Provisioning, the Dynamic Provisioning must be installed on the storage system.
Before you use the capacity saving function, Dynamic Provisioning and dedupe and compression must be installed on the storage system.
Before you use Dynamic Tiering, Dynamic Provisioning and Dynamic Tiering must be installed on the storage system.
You need the Dynamic Tiering license to access the total capacity of the pool with the tier function enabled.
For Dynamic Provisioning, Dynamic Tiering, and active flash, the same license capacity as the DP-VOLs is required.
For Dynamic Tiering, and active flash, the same license capacity as the pool capacity is required.
For active flash, the same license capacity as the pool capacity is required.
Before you use active flash, the Dynamic Provisioning, and Dynamic Tiering software must be installed on the storage system.
If the DP-VOLs of Dynamic Provisioning or Dynamic Tiering are used for the primary volumes and secondary volumes of ShadowImage, TrueCopy, Universal Replicator, Volume Migration, global-active device, or Thin Image, you will need the ShadowImage, TrueCopy, Universal Replicator, Volume Migration, global-active device, and Thin Image licenses for the total pool capacity in use.
If you expand a Dynamic Provisioning pool that contains Thin Image pairs and snapshot data, the licensed capacity for both Dynamic Provisioning and Thin Image is required.
If you exceed the licensed capacity, you will be able to use the additional unlicensed capacity for 30 days. For more information about temporary license capacity, see the System Administrator Guide.
Shared memory requirements
The amount of additional shared memory needed depends on the size of the Dynamic Provisioning, Thin Image and Dynamic Tiering pools.
Shared memory is installed and removed by your service representative. For details about the installation and removal of shared memory, see the hardware reference guide for your storage system.
Cache management device requirements
Cache management devices are used to manage the cache associated with volumes (LDEVs). Each volume (LDEV) requires at least one cache management device. An LDEV that is not a DP-VOL requires one cache management device. For an LDEV that is a DP-VOL, you need to calculate the number of cache management devices required.
The storage system can manage 65,280 cache management devices:
The View Management Resource Usage window in Device Manager - Storage Navigator displays the number of cache management devices in use and the maximum number of cache management devices. To open the View Management Resource Usage window, click Actions and then select View Management Resource Usage.
Calculating the number of cache management devices required for DP-VOLs
A volume that is not a DP-VOL requires one cache management device. The number of cache management devices that a DP-VOL requires depends on the capacity of the V-VOL (capacity of the user area) and the maximum capacity of the cache management device.
The following table explains the relationship between the pool volume attribute and the maximum capacity of the cache management device.
|
Maximum capacity of cache management device | ||
|
Pool attribute of V-VOL |
MB (TB) |
Blocks |
|
Internal volume |
3,145,548 MB (2.99 TB) |
6,442,082,304 blocks |
|
External volume |
3,145,548 MB (2.99 TB) |
6,442,082,304 blocks |
Use the following formula to calculate the number of cache management devices that a DP-VOL requires. In this formula, the user-specified capacity is the user area capacity of a V-VOL.
ceiling(user-specified-capacity / max-capacity-of-cache-management-device)
where
- ceiling: The value enclosed in ceiling( ) must be rounded up to the nearest whole number.
- For a DP-VOL with the deduplication or compression function enabled, use twice the number of the cache management devices calculated by this formula.
Pool specifications and requirements
A pool is a set of volumes reserved for storing Dynamic Provisioning write data.
|
Items |
Requirements |
|
Pool capacity |
Calculate pool capacity using the following formula:
4200 in the formula is the management area size of the pool-VOL with System Area.
floor( ): Truncates the value calculated from the formula in parentheses after the decimal point (that is, round down to nearest whole number). Following are minimum and maximum capacity sizes for one pool:
Following are maximum capacity sizes of all pools in a storage storage system:
If you operate a pool without monitoring the free space, then ensure that the total DP-VOLs capacity remains smaller than the pool capacity. |
|
Max number of pool-VOLs |
From 1 to 1,024 volumes (per pool). A volume can be registered as a pool-VOL to one pool only. |
|
Maximum number of pools |
The maximum number of pools includes the following pool types:
|
|
Increasing capacity |
You can increase pool capacity dynamically. Best practice is to add pool-VOLs to increase capacity by one or more parity groups. |
|
Reducing capacity |
You can reduce pool capacity by removing pool-VOLs. |
|
Deleting |
You can delete pools that are not associated with any DP-VOLs or with any Thin Image pairs or Thin Image snapshot data. |
|
Thresholds |
|
|
Data allocation unit |
42 MB The 42-MB page corresponds to a 42-MB continuous area of the DP-VOL. Pages are allocated for the pool volumes only when data has been written to the area of the DP-VOL. |
|
Tier (Dynamic Tiering and active flash) |
Defined based on the media type (see Drive type for a Dynamic Tiering and active flash tier, below). Maximum 3 tiers. |
|
Maximum capacity of each tier (Dynamic Tiering and active flash) |
|
For a pool which is associated with DP-VOLs that are enabled of the capacity saving function, the following table indicates the maximum capacity of the total pool volumes and the number of pools that can be created.
| Storage system | Added shared memories | Maximum capacity of the total pool volumes for one pool (PB) | Number of pools that can be created |
| Virtual Storage Platform G350 or Virtual Storage Platform F350 | Base | 0.29 | 3 |
| Extension 1 | 1.6 | 16 | |
| Extension 2 | 4.4 | 45 | |
| Extension 3 | Not available | Not available | |
| Virtual Storage Platform G370 or Virtual Storage Platform F370 | Base | 1.6 | 16 |
| Extension 1 | 4.4 | 45 | |
| Extension 2 | 8.05 | 64 | |
| Extension 3 | Not available | Not available | |
| Virtual Storage Platform G700 or Virtual Storage Platform F700 | Base | 1.6 | 16 |
| Extension 1 | 4.4 | 45 | |
| Extension 2 | 8.05 | 64 | |
| Extension 3 | 12.5 | 64 | |
| Virtual Storage Platform G900 or Virtual Storage Platform F900 | Base | 4.4 | 45 |
| Extension 1 | 8.05 | 84 | |
| Extension 2 | 12.5 | 128 | |
| Extension 3 | 16.6 | 128 |
Pool-VOL requirements
Pool-VOLs make up a DP pool.
|
Item |
Requirements |
|
Volume type |
Logical volume (LDEV) While pool-VOLs can coexist with other volumes in the same parity group, for best performance:
Pool-VOLs cannot be used for any other purpose. For instance, you cannot specify the following volumes as Dynamic Provisioning, Dynamic Tiering, and active flash pool-VOLs:
The following volume cannot be specified as a pool-VOL for Dynamic Tiering:
If pool-VOLs are LDEVs created from the parity group with accelerated compression enabled, these pool-VOLs must be applied to one pool. |
|
Emulation type |
OPEN-V |
|
RAID level for a Dynamic Provisioning pool |
You can use one of the following RAID levels:
Pool-VOLs of RAID 5, RAID 6, RAID 1, and external volumes can coexist in the same pool. For pool-VOLs in the same pool:
|
|
RAID level for a Dynamic Tiering or active flash pool |
You can use one of the following RAID levels:
Pool-VOLs of RAID 5, RAID 6, RAID 1, and external volumes can coexist in the same pool. For pool-VOLs in the same pool:
|
|
Data drive type for a Dynamic Provisioning pool |
SSD, FMD DC2, SAS15K, SAS10K, SAS7.2K, and external volumes can be used as the data drive type. These data drive types can coexist in the same pool. Cautions:
|
|
Data drive type for a Dynamic Tiering or active flash pool |
SAS15K, SAS10K, SAS7.2K, SSD, FMD DC2, and external volumes can be used as the data drive type. These data drive types can coexist in the same pool. If active flash is used, SSDs must be installed in advance. Caution: If multiple data drives coexist in the same pool, we recommend not using data drives that are the same types and different capacity sizes. |
|
Volume capacity |
Internal volume: From 8 GB to 2.9 TB External volume: From 8 GB to 4 TB External volume with the data direct mapping attribute: From 8 GB to 256 TB |
|
LDEV format |
The LDEV format operation can be performed on pool-VOLs only when all of the following conditions are satisfied:
|
|
Path definition |
You cannot specify a volume with a path definition as a pool-VOL. |
DP-VOL requirements
|
Items |
Requirements |
|
Volume type |
DP-VOL (V-VOL) The LDEV number is handled in the same way as for normal volumes. |
|
Maximum number of DP-VOLs |
For VSP G350 and VSP F350:
For VSP G370 and VSP F370:
For VSP G700 and VSP F700:
For VSP G900 and VSP F900:
|
|
Volume capacity |
Total maximum volume capacity is as follows:
However, if DP-VOLs of the capacity saving function are enabled and are associated with a pool, then the maximun volume capacity is the value which is deducted from the total capacity (10% of the total capacity of DP-VOLs before the capacity saving). |
|
Path definition |
Available. |
|
LDEV format |
Available. Quick Format is not available. System option mode (SOM) 867 ON: When you format an LDEV on a DP-VOL, the capacity mapped to the DP-VOL is released to the pool as free space. When you format a DP-VOL, the storage system releases the allocated page area in the DP-VOL. The quick format operation cannot be performed. If the LDEV format is applied to V-VOLs that are enabled for full allocation, the used capacity of the pool is not changed before the LDEV format is applied. Caution:
|
The following table indicates the maximum capacity of the total DP-VOLs whose Capacity Saving setting is Deduplication and Compression or Compression.
| Storage system | Added shared memories | Maximum capacity of the total DP-VOLwhose Capacity Saving setting is Deduplication and Compression or Compression (PB) |
| Virtual Storage Platform G350 or Virtual Storage Platform F350 | Base | 0.2175 |
| Extension 1 | 1.2 | |
| Extension 2 | 3.3 | |
| Extension 3 | Not available | |
| Virtual Storage Platform G370 or Virtual Storage Platform F370 | Base | 1.2 |
| Extension 1 | 3.3 | |
| Extension 2 | 6.0375 | |
| Extension 3 | Not available | |
| Virtual Storage Platform G700 or Virtual Storage Platform F700 | Base | 1.2 |
| Extension 1 | 3.3 | |
| Extension 2 | 6.0375 | |
| Extension 3 | 9.375 | |
| Virtual Storage Platform G900 or Virtual Storage Platform F900 | Base | 3.3 |
| Extension 1 | 6.375 | |
| Extension 2 | 9.375 | |
| Extension 3 | 12.45 |
Operating system and file system capacity
When initializing a DP-VOL operating systems and file systems will consume some Dynamic Provisioning pool space. Some combinations initially take up little pool space, while other combinations take as much pool space as the virtual capacity of the DP-VOL.
The following table shows the effects of some combinations of operating system and file system capacity. For more information, contact your service representative.
|
OS |
File System |
Metadata Writing |
Pool Capacity Consumed |
|
Windows Server 2003, Windows Server 2008* |
NTFS |
Writes metadata to first block. |
Effective reduction of pool capacity: Small (one page) If file update is repeated, allocated capacity increases when files are updated (overwritten). Therefore, the effectiveness of reducing the pool capacity consumption decreases. |
|
Linux |
XFS |
Writes metadata in Allocation Group Size intervals. |
Effective reduction of pool capacity: Depends upon allocation group size. The amount of pool space consumed will be approximately [DP-VOL Size] × [42 MB/Allocation Group Size] |
|
Ext2 Ext3 |
Writes metadata in 128-MB increments. |
Effective reduction of pool capacity: About 33% of the size of the DP-VOL. The default block size for these file systems is 4 KB. This results in 33% of the DP-VOL acquiring DP pool pages. If the file system block size is changed to 2 KB or less then the DP-VOL Page consumption becomes 100%. | |
|
Solaris |
UFS |
Writes metadata in 52-MB increments. |
No effective reduction of pool capacity. Size of DP-VOL. |
|
VxFS |
Writes metadata to the first block. |
Effective reduction of pool capacity: Small (one page). | |
|
AIX |
JFS |
Writes metadata in 8-MB increments. |
No effective reduction of pool capacity. Size of DP-VOL. If you change the Allocation Group Size settings when you create the file system, the metadata can be written to a maximum interval of 64 MB. Approximately 65% of the pool is used at the higher group size setting. |
|
JFS2 |
Writes metadata to the first block. |
Effective reduction of pool capacity: Small (one page). | |
|
VxFS |
Writes metadata to the first block. |
Effective reduction of pool capacity: Small (one page). | |
|
HP-UX |
JFS (VxFs) |
Writes metadata to the first block. |
Effective reduction of pool capacity: Small (one page). |
|
HFS |
Writes metadata in 10-MB increments. |
No effective reduction of pool capacity. Size of DP-VOL. | |
|
* In a Windows environment, both Normal Format and Quick Format are commonly used. In this environment, Quick Format consumes less thin provisioning pool capacities than Normal Format:
| |||
V-VOL page reservation requirement
The V-VOL full allocation is performed in a range less than the depletion threshold size of the pool. If the capacity of V-VOLs is larger than the depletion threshold size, the full allocation operation is rejected.
- Pools that contain pool volumes belonging to a parity group with accelerated compression enabled
- Pools with capacity saving enabled
Use the following formula to calculate the reserved page capacity for each pool. In the formula, the value enclosed in ceiling( ) must be rounded up to the nearest whole number.
Reserved capacity for each pool [block] = ceiling(CV-capacity-of-V-VOL [block] / 86016) * 86016 + ceiling(CV-capacity-of-V-VOL [block] / 6442082304) * 4 * 86016 - used-capacity-of-V-VOL [block]
Tier relocation rules, restrictions, and guidelines
- Performance monitoring, using both Auto and Manual execution modes, observes the pages that were allocated to DP-VOLs prior to the start of the monitoring cycle and the new pages allocated during the monitoring cycle. Pages that are not allocated during performance monitoring are not candidates for tier relocation.
- Tier relocation can be performed concurrently on up to eight pools. If more than eight pools are specified, relocation of the ninth pool starts after relocation of any of the first eight pools has completed.
- If Auto execution mode is specified, performance monitoring may stop about one minute before to one minute after the beginning of the next monitor cycle start time.
- The amount of relocation varies per cycle. In some cases, the cycle may end before all relocation can be handled. If tier relocation does not finish completely within the cycle, relocation to appropriate pages is executed in the next cycle.
- Calculating the tier range values will be influenced by the capacity allocated to DP-VOLs with relocation disabled and the buffer reserve percentages.
- While a pool-VOL is being deleted, tier relocation is not performed. After the pool-VOL deletion is completed, tier relocation starts.
- Frequency distribution is unavailable when there is no data provided by performance monitoring.
- While the frequency distribution graph is being created or the tier range values are being calculated, the frequency distribution graph is not available. The time required for determining the tier range values varies depending on the number of DP-VOLs and total capacity. The maximum time is about 20 minutes.
- To balance the usage levels of all parity groups, rebalancing may be performed after several tier relocation operations. If rebalancing is in progress, the next cycle of tier relocation might be delayed.
The following table lists monitoring and execution conditions and specifies the data collection status, fixed monitoring status, and tier relocation operations for each condition. The latest fixed monitoring information is referenced when tiers are relocated.
|
Monitoring information or execution conditions |
Status of data collection in progress |
Status of fixed monitoring information used in tier relocation |
Tier relocation operations |
Solutions |
|
Unallocated pages. |
Pages are not monitored. |
No monitoring information about pages. |
Tiers of the pages are not relocated. |
Unnecessary. After the pages are allocated, monitoring and relocation are performed automatically. |
|
Zero data is discarded during data monitoring. |
Monitoring on pages is reset. |
Only monitoring information about pages is invalid. |
Tiers of the pages are not relocated. |
Unnecessary. After the pages are allocated, monitoring and relocation are performed automatically. |
|
V-VOL settings do not allow tier relocation. |
Volume is monitored. |
Monitoring information about the volume is valid. |
If the tier relocation setting is being disabled at the performance monitoring finish time, tiers of the volume are not relocated. |
N/A |
|
When V-VOLs are deleted. |
Volume is not monitored. |
Only monitoring information about the volume is invalid. |
Tier relocation of the volume is suspended. |
N/A |
|
When execution mode is changed to
|
Suspended. |
Monitoring information collected before suspension is valid. |
Suspended. |
Collect the monitoring information again if necessary.1 |
|
When the power switch is power ON or OFF. |
Monitoring is suspended by powering OFF and is not resumed even after powering ON.1 |
Monitoring information collected during the previous cycle is continuously valid. |
Tier relocation is suspended by powering OFF and is resumed after powering ON. |
Collect the monitoring information again if necessary.1 |
|
The monitoring information of the volume is not collected at the present moment. In the next monitoring period, the monitoring information will be collected. |
Monitoring information is invalid and the volumes need to be monitored. |
Tier relocation to volumes is suspended. |
Collect the monitoring information again if necessary.1 |
|
S-VOL of the following products when the initial copy operation is performed:
|
Monitoring information is collected continuously, but the monitoring of the volumes is reset.2 |
No effect on the fixed monitoring information. The monitoring information collected during the previous cycle continues to be valid. |
Tier relocation to volumes is suspended. |
Collect the monitoring information again if necessary.1 |
|
Continued. |
Fixed monitoring information is invalid because the monitoring information was discarded. If monitoring is set to the continuous mode, weighted data calculated by using the monitoring information in past periods is also discarded. |
Suspended. |
Relocate tiers again.1 |
|
When pool-VOLs are deleted. |
Continued. |
Monitoring information is invalid temporarily. The monitoring information is calculated again after deleting of pool-VOLs.4 |
Deleting the pool-VOL stops the tier relocation. The process resumes after the pool-VOL is deleted. |
N/A |
|
When cache is blocked. |
Continued. |
No effect on the fixed monitoring information. The monitoring information collected during the previous cycle continues to be valid. |
Suspended.5 |
After recovering the faulty area, relocate tiers again.1 |
|
When an LDEV is blocked (pool-VOL or V-VOL). |
Continued. |
No effect on the fixed monitoring information. The monitoring information collected during the previous cycle continues to be valid. |
Suspended.5 |
After recovering the faulty area, relocate tiers again.1 |
|
When the depletion threshold of the pool is nearly exceeded during relocation. |
Continued. |
No effect on the fixed monitoring information. The monitoring information collected during the previous cycle continues to be valid. |
Suspended.5 |
Add pool-VOLs, then collect monitoring information and relocate tiers again.1 |
|
When execution mode is
|
At the end time of execution cycle, data monitoring stops. |
The monitoring information collected before monitoring performance stops is valid. |
Suspended.5 |
Unnecessary. The relocation is performed automatically in the next cycle. |
|
When execution mode is
|
Suspended. |
The monitoring information collected before suspension is valid. |
Continued. |
Collect the monitoring information again if necessary.1 |
|
Notes:
| ||||