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2 Intern
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222 Posts
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2462
March 9th, 2016 11:00
Write cache disabled due to battery failure
We have an older CX4-120, and the internal batteries have failed. It's too expensive to replace at this point, since the array is already protected by datacenter power protection. However, due to the battery issue, the write cache has been disabled, and that is leading to extreemly poor performance.
This is just a DR array, and we are not too worried about the battery issue.
Is there a way to over-ride the write cache and force it to be enabled???
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kelleg
4 Operator
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4.5K Posts
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March 9th, 2016 12:00
Pretty sure you need two conditions to enable the Write cache:
1. AC power to the SP's
2. Battery sense cable is providing the signals that show the battery is in good condition (this goes along with the weekly battery test).
As far I know there is no way to bypass these and keep the Write cache enabled.
glen
ZaphodB
195 Posts
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March 17th, 2016 07:00
The function of the SPS is to monitor the availability of power, signal the controllers to perform a controlled shutdown which preserves data integrity in case of power loss, and to supply sufficient battery power to the controllers and first DAE to facilitate that safe shut down.
Your building UPS/generator does not do that.
If the unit is off of support, you could consider getting a replacement SPS on the open market; it should only be a few hundred dollars. If you elect to go that route, my advice would be to look for one that is rebuilt with new batteries, and comes with a warranty from the vendor, rather than just a 'pull' which may be several years old and fail almost immediately.
AnkitMehta
3 Apprentice
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1.4K Posts
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April 4th, 2016 03:00
EMC did have DC Powered CLARiiON CX4 arrays which did not use a standby power supply.
I would say remove both the SPS's and let it run only on DC which it is already. I am not sure it will work for you or not but you can let us know, right?
Refer my Old Post Response and attachment for CX4 DC: Enable Write Cache on a CX without SPS Battery