| What's New |
| Q1. |
What is Serial Attached SCSI? |
| A1. |
Serial Attached SCSI (SAS) is the logical evolution that satisfies the enterprise data center requirement of scalability, performance, reliability and manageability, while leveraging a common electrical and physical connection interface with Serial ATA (SATA). This compatibility provides users with unprecedented choices for server and storage subsystem deployment. |
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| Q2. |
Why was SAS developed? |
| A2. |
SAS was developed to address anticipated I/O and direct attach storage requirements in the future. It provides universal interconnect with SATA, while offering logical SCSI compatibility along with SCSI reliability, performance and manageability.
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| Q3. |
What are the end user benefits of Serial Attached SCSI? |
| A3. |
Key end user benefits include enterprise class robustness, investment protection in compatible SCSI software and middleware and the choice of direct-attach storage devices (SAS or SATA). In addition, greater performance, longer cabling distances, smaller form factors and greater addressability will all lead to a new level of flexibility when deploying mainstream data center servers and subsystems. Since SAS is based on the foundation of the industry-leading SCSI specification, reliability and peace of mind will satisfy user's needs for continuity in the data center. |
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| Q4. |
How does Serial Attached SCSI benefit the storage industry? |
| A4. |
SAS leverages the proven SCSI technologies that customers expect in data center environments, providing robust solutions and generational consistency. It is based on a serial interface, allowing for increased device support and bandwidth scalability, and reducing the overhead impact that challenges today's SCSI environments. It utilizes SATA development work on smaller cable connectors, providing customers a downstream compatibility with desktop class ATA technologies.
Simplified routing will enable a new generation of dense devices, such as small form factor hard drives, enabling storage solutions to scale externally.
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General Questions
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| Q1. |
Is the Smart Array P400 controller backwards compatible to Ultra2, Ultra3, and Ultra320 SCSI? |
| A1. |
No, serial attached SCSI controllers are not compatible with parallel SCSI devices. |
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| Q2. |
Will the Smart Array P400 support external drives? |
| A2. |
No. The Smart Array P400 has 8, 3Gb SAS ports supporting two internal connections using the controllers x4 Wide SAS Ports. |
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| Q3. |
What RAID levels are supported by the Smart Array P400? |
| A3. |
The SA-P400/256 supports RAID 0, 1, 1+0 and 5. RAID 6 (Advanced Data Guarding) is available by adding either the BBWC upgrade or the 512 BBWC upgrade. |
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| Q4. |
What is Online Drive Flashing? |
| A4. |
Online Drive Flashing is available on the SA-P400. Previously, when hard disk drive (HDD) firmware required upgrading the storage had to be taken offline before a new firmware image could be loaded. With Online Drive Flashing, you can now download an updated HDD firmware image to the SA-P400 and update all of your SAS HDDs the next time you reboot the server. This greatly reduces the time involved in updating disk drive firmware. |
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| Q5. |
What is Recovery ROM? |
| A5. |
Recovery ROM provides a unique redundancy feature that helps ensure against controller availability. During the flash process, a new version of the firmware can be flashed to the ROM while the controller maintains the last known working version of firmware. If the firmware becomes corrupt, the controller will revert back to the last known version of firmware and continue operating. This reduces the risk of flashing new firmware to the controller. |
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Common questions
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| Q1. |
What is mirror splitting and recombining? |
| A1. |
Mirror Splitting and recombining allows the user to divide a RAID1 array into 2 RAID0 array's. Later you can combine 2 RAID0 array's into a single RAID1 array. ACU allows the user to combine any two RAID 0 arrays of the same size together and select which drive contains the data that you want to keep. This feature is currently only available offline. The user must boot to the Smart Start CD and run ACU from there.
Typically this feature is used when testing out a software patch. The user could split the mirror as a means to save the current data. They could then perform any type of destructive software update they choose and either keeps the resulting data set or revert back to the old data. Another application is cloning.
BBWC is not required for this feature to be enabled.
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| Q2. |
What is capacity expansion? |
| A2. |
Capacity expansion is the process of adding physical drives to the array that has already been configured. The logical drives (or volumes) that exist in an array before the expansion takes place are unchanged. Only the amount of free space in the array changes.
A battery is required for this feature.
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| Q3. |
Are there any limitations on rebuilds? |
| A3. |
If the system is rebooted during a rebuild, the array rebuild will start all over. |
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| Q4. |
How many hard drives does the P400 support? |
| A4. |
The P400 supports up to 18 drives and up to 3TB of total storage (6 x 500GB HDD). |
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| Q5. |
How is the P400 controller that is used in the 380/385 unique? |
| A5. |
The P400 controller used in the 380/385 has the same features and functionality as the standard P400 which is used in all other servers. The difference is that the connector is located at the back (or backside) of the controller in order to better accommodate the chassis design of those servers. |
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| Technical questions - cache/memory |
| Q1. |
Does the Smart Array P400 have battery-backed cache and what features require BBWC? |
| A1. |
On the Smart Array P400, a battery module is available for the 256MB cache configuration and is standard on the 512MB cache module. When the Smart Array P400 is equipped with its innovative transportable battery-backed cache, 1) In the event of a controller failure or server failure, the Smart Array cache can be removed from the SA-P400 controller and placed on another SA-P400 controller board; the cached data will be flushed to the disk drives. 2) The cache batteries provide up to 2 days of battery life.
The following features require BBWC: RAID 6 with ADG, array expansion, logical drive extension, RAID migration, and stripe size migration.
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| Q2. |
Will the SA-P400 support standard server DIMM memory? |
| A2. |
No. The controller DIMM socket is not designed to accommodate standard DIMM memory because standard server memory DIMM does not support battery back-up and does not meet fault tolerant standards for a RAID controller. |
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| Q3. |
What are the default RAID stripe size settings? |
| A3. |
When using ORCA Version 2.54 and later the default settings are as follows:
- RAID 0, 1, 1+0 - 128 KB
- RAID 5 - 64 KB
- RAID 6 (ADG) - 16 KB
When using ACU CLI Version 7.20 and later the default setting are as follows:
- RAID 0, 1, 1+0 - 128 KB
- RAID 5 - 64 KB
- RAID 6 (ADG) - 16 KB
When using ACU Version 7.50 and later the default setting are as follows:
- RAID 0, 1, 1+0 - 128 KB
- RAID 5 - 64 KB
- RAID 6 (ADG) - 16 KB
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| Q4. |
Is Drive Write Cache available on HP SATA drives? |
| A4. |
Yes, however HP ships SATA drives with Drive Write Cache (DWC) disabled. The preset configuration was selected to provide greater safety for our customer's drive data in case of sudden power loss, when there is no battery on the controller to protect the cache.
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| Q5. |
Can Drive Write Cache be enabled on the controller and SATA drives? |
| A5. |
Yes, please see the attached presentation for the latest servers and controllers that allow for Drive Write Cache to be enabled.
WARNING: Enabling DWC may result in loss of data if power is lost to the server and there is no power protection configured for the server. When Drive Write Cache is configured, the following best practices should be used to protect the data in case of power loss: Install a redundant power supply in the server (if available for that server). If redundant power supplies are used and one power supply fails, temporarily disable Drive Write Cache until a replacement power supply has been installed. If redundant power supplies are used, add an additional layer of power protection by connecting each power supply in the server to a separate Uninterruptible Power Supply (UPS). If multiple UPSs are used, add an additional layer of power protection by connecting each UPS to a different AC circuit.
How to Enable Write Cache on SATA HDDs for HP ProLiant ML100 series and ML310DL320 Servers DWC
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| Service and Support |
| Q1. |
Does the Smart Array P400 controller use the same configuration utilities and management software as the other Smart Array controllers? |
| A1. |
Yes, this is the Smart Array Advantage. All Smart Array controllers use the same configuration utility (ACU) diagnostic (ADU) and management software (HP Insight Manager) as the entire Smart Array family of products. In addition, the SA-P400 also provides Options ROM Configuration for Arrays (ORCA) that allows a simplified configuration tool at the time of controller boot. |
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| Q2. |
Which ProLiant servers are supported by the Smart Array P400? |
| A2. |
The Smart Array P400 is supported on most current generation ProLiant 300 and 500 series servers. View a complete, up-to-date list of supported servers. |
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| Q3. |
Which operating systems will be supported by the Smart Array P400? |
| A3. |
SA-P400 will support several operating systems including: Windows 2003 and Linux. Please refer to OS support for a complete list. |
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