Thanks for reading my question! How to enable HDD's Write Cache when Volume(RAID5) is in Degrade or Rebuild state?

[tan000]

When Volume(RAID-5) enter degrade or Rebuild state, Writing to Volume is too slow because HDD's Write Cache is disabled automatically. 

How to enable HDD's Write Cache when Volume(RAID5) is in Degrade or Rebuild state? 

My Version: Intel VROC RSTe Win 6.1.0.1247

[BrusC_Intel]

Hello, tan000.

Good day,

Thank you for contacting the Intel Community Support.

I checked your ticket regarding the HDD write cache, I will be glad to assist you.

I will need more information to properly handle or route your inquiry, please let me know the following:

- Full system report generated by the Intel System Support Utility:

https://downloadcenter.intel.com/download/25293/Intel-System-Support-Utility-for-Windows-

- System report from the VROC/RST window (Help > System report > Save)

Best regards,

Bruce C.

Intel Customer Support Technician

A Contingent Worker at Intel

[tan000]

Thanks for your reply.

The attached files are what you requested.

Intel_SSU_info.txt is saved by SSU.exe.

SystemReport.txt is saved by VROC.

It seems only one file can be attache here . I will attache other file in the next message.

In Degrade or Rebuild RAID State, is there some method to enable HDD's Write Cache?

Because when HDD Write cache is disabled, the Write-access performance is too slow to use as a product.

Best Regards!

[tan000]

Have a good day!

Other file is attached.

[BrusC_Intel]

Hello, tan000.

Good day,

Thank you very much for the response and all the information.

I reviewed if it's possible to enable it while it is degraded, but in this case, rebuilding the RAID takes priority, so this option will not be available until the status is normal again.

If you have other questions and I can be of assistance, please let me know.

Best regards,

Bruce C.

Intel Customer Support Technician

A Contingent Worker at Intel

[tan000]

Thanks for your kind reply.

Would you please to tell me how to increase write performance in degrade state and rebuild State?

In degraded or rebuild state, Disk Data Cache Enable is shown, but Sequential Write performance is

too slow(8MB/s) than normal State over 400MB/s. I think that in fact Disk Data Cache work as disable.

Please see the attache file to view performance data in RAID normal, Degrade, Rebuild states.

BTW, in Intel VROC 6.1 PV Release Notes, the following is Written:

8.4 Expect Longer Rebuild Times for RAID 5 

On a RAID 5 volume, disk cache is being turned off when a volume is degraded. 

Due to this, the rebuilding times have increased expectedly until the rebuild is completed, 

and disk cache is enabled again.

This extends to drives being added to a RAID 5 volume as well.

[BrusC_Intel]

Hello, tan000.

Thank you for the response and the details.

There is no particular method or adjustment to increase the performance while the RAID is in this state, it is recommended to replace the drive to prevent data loss in case something happens to one of the remaining drives.

Best regards,

Bruce C.

Intel Customer Support Technician

A Contingent Worker at Intel

[tan000]

Hi, Thanks a lot for your reply!

OK, I see. There is no method to enable HDD Data Cache when in degrade or rebuild state.​

So I can not use the M/B and VROC in our production.

[BrusC_Intel]

Hello, tan000.

I completely understand.

Since there are no options we can provide, let me know if you have any other questions or if we can proceed to close the ticket.

Bruce C.

Intel Customer Support Technician

A Contingent Worker at Intel

[tan000]

Hi,　bruce.coto

Please close the ticket.

I will report you a VROC read error while Volume's write-back cache is enabled in a new ticket.

Best Regards!​