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Cannot change Write Cache Polity from Write Through to Write Back
Hello,
We've two Raid 10 created from Dell SAS drives on a Dell PowerEdge R730 - PERC H830 Adapter.
When the Virtual disks were created the Write cache policy selected was the Write Back. Even so, for some reasons both raids were automatically created with Write-Through policy.
We've tried change it back from iDrac, OMSA, CTRL+R Configuration utility as well from the BIOS. Nothing seems to work.
We've checked the battery and it looks fine.
We've checked the VDs if they have initialized, we've even run a reinitialization of them.
When I choose WRITE BACK, it accepts the request (no error), and even the SA logs show command accepted successfully. System has been rebooted several times since then ( that didn't helped either ).
Any clue what else i can do, or perhaps i didn't do the needed steps in the right order.
Any help is highly appreciated in order to figure out if there's anything else that can be done before opening a hardware call to Dell
Thanks and Best regards,
Alex
Dell-JimmyP
311 Posts
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March 7th, 2018 13:00
Hi,
There is a fix in firmware Dell PERC H730/H730P/H830/FD33xS/FD33xD Mini/Adapter RAID Controllers firmware version 25.5.4.0006
-Fixes an issue where the battery could inadvertently change to WT during a transparent learn cycle.
I recommend updating to latest firmware version.
Please send a private message with your service tag to ensure we have all appropriate information on your system.
Thank you,
AlexMilotin
3 Posts
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March 7th, 2018 23:00
Hello,
Thank you for the quick reply. The weird part regarding this is why is not happening on a system which is actually the same in matter hardware components and drivers/Firmware version.
The upgrade to latest version will follow in the upcoming days.
In the mean time can you please tell me how exactly i can send you a private message ? I can't seem to have the option available .
Thank you
Dell-JimmyP
311 Posts
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March 8th, 2018 11:00
Hi,
Thank you for the service tag.
Even though the hardware is the same on the servers, the components are different. There may be an issue with the batteries on that is going to write through. I suggest going ahead with the recommended controller firmware update if not at that level already.
Look in the tty log and see if anything is going on with battery in the background. During the learn cycle, the cache policy will change to write through until the battery is charged once more. You should see something similar to:
AlexMilotin
3 Posts
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March 12th, 2018 13:00
Hello again.
I've exported the log but i couldn't found anything like the lines you've mentioned. Before running the full upgrade over the system to see if the issue gets fixed, is there anyway i can send you the log to take a look over it.
Perhaps there's something that i missed between the thousands lines.
Later edit:
I've done a full system upgrade to latest SUU available and retry changing the Write Cache Policy. Still not working. I've selected the logs from the last 2 actions (hopefully).
Thanks