Re: Enable No-Battery Write Cache (3174 Views)
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Occasional Contributor
Rob Baumstark
Posts: 2
Registered: ‎03-07-2007
Message 1 of 6 (6,967 Views)

Enable No-Battery Write Cache

I recently put together a box to be used for some basic file=sharing from old parts that I scrounged up. The main bit being some old disk shelves from an HSG80 array we got rid of, and a SmartArray 6404 that was no-longer being used from something else. The batteries on the 6404 are long-dead, but considering that the entire system is protected by datacenter-wide UPS, and I'm using it for non-important stuff where I usually want my result fast and don't care about the data afterwards, I would like to get my write-caching working again. I've found there is an option to enable "No-Battery Write Cache" which sounds like exactly what I want, but I can't make it work.

The default display of a "ctrl slot=1 show detail" in the acu-cli shows me: (serial numbers removed)

Smart Array 6400 in Slot 1
Bus Interface: PCI
Slot: 1
Serial Number: xxxxxxxxxxxxx
Cache Serial Number: xxxxxxxxx
RAID 6 (ADG) Status: Enabled
Controller Status: OK
Chassis Slot:
Hardware Revision: Rev B
Firmware Version: 2.84
Rebuild Priority: Medium
Expand Priority: Medium
Surface Scan Delay: 3 secs
Post Prompt Timeout: 15 secs
Cache Board Present: True
Cache Status: Temporarily Disabled
Accelerator Ratio: 75% Read / 25% Write
Total Cache Size: 192 MB
No-Battery Write Cache: Disabled
Cache Backup Power Source: Batteries
Battery/Capacitor Count: 2
Battery/Capacitor Status: Failed (Replace Batteries)
SATA NCQ Supported: False

All is good and as I expect - the cache is temp-disabled due to a dead battery, and no-battery write cache is disabled. The problem begins when I issue the command

ctrl slot=1 modify nbwc=enable

It completes without giving me any kind of error message (I also tried a 'dwc=enable' command, and it errored telling me it was not supported), but does not have the desired result. re-running a show detail now shows:

Smart Array 6400 in Slot 1
Bus Interface: PCI
Slot: 1
Serial Number: xxxxxxxxxxxx
Cache Serial Number: xxxxxxxxxx
RAID 6 (ADG) Status: Enabled
Controller Status: OK
Chassis Slot:
Hardware Revision: Rev B
Firmware Version: 2.84
Rebuild Priority: Medium
Expand Priority: Medium
Surface Scan Delay: 3 secs
Post Prompt Timeout: 15 secs
Cache Board Present: True
Cache Status: Not Configured
Accelerator Ratio: 75% Read / 25% Write
Total Cache Size: 192 MB
No-Battery Write Cache: Disabled
Cache Backup Power Source: Batteries
Battery/Capacitor Count: 2
Battery/Capacitor Status: Failed (Replace Batteries)
SATA NCQ Supported: False

So..., no-battery write cache is still disabled, and the cache status has changed from temp-disabled to not-configured. Any attempt to configure the cache (the only way I've found so far that has an effect is to enable array-accelerator for a logical drive) results in the config returning to the original state - temp-disabled.

To summarize, the no-battery-write-cache setting is only having the effect of toggling my cache status beteen temp-disabled and not-configured. How do I get my write-cache enabled without buying batteries?
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Honored Contributor
Zygmunt Krawczyk
Posts: 825
Registered: ‎09-05-2003
Message 2 of 6 (6,967 Views)

Re: Enable No-Battery Write Cache

"No-Battery Write Cache" option is compatible only with recent Smart Arrays for which the battery is optional. For Smart Array 6404 the battery is required, so you can't enable write cache without battery.
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Respected Contributor
Trygve Henriksen
Posts: 336
Registered: ‎08-18-2003
Message 3 of 6 (6,967 Views)

Re: Enable No-Battery Write Cache

Maybe it's possible to remove the batteries and rebuild the pack with new cells?
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Regular Advisor
Louis Henninger_1
Posts: 169
Registered: ‎04-09-2007
Message 4 of 6 (6,943 Views)

Re: Enable No-Battery Write Cache

I have a friend that purchased a "new" battery pack on ebay....for about 18.00 each plus shipping. They were not HP Branded spares (usually made in Germany), but after-market from China....They're still working without issue.

He was looking into just replacing the individual cells(Varta V500HRT, 3 each per pack), but cost for the Varta cells were more that a HP Branded Battery Pack.

 

Regards,

 

Louis

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Advisor
todd bailey
Posts: 22
Registered: ‎01-06-2010
Message 5 of 6 (3,175 Views)

Re: Enable No-Battery Write Cache

I refused to pay the high replacement battery costs, as I have 7 SA controllers running.  I went to radio shack and purchased a series of 3 and 4 cell aaa battety holders and to Harbour Frieght tools and purchased about a dozen of their aaa ni-mh batteries.

 

After charging the aaa batteries, I installed them in the holders. After removing the long since dead hp battery packs,  I soldered the battery leads to the terminals of the controller,  Remember "red goes to + and black goes to -"

these are clearly marked on the boards and memory cards.

 

my sa -5304, hp 6402, sa p600 and sa p800 and now quite happy with the new battery packs.

 

While not as clean as a oem replacement, this allows me to replace all the batteries for much less than a single pair of oem packs.

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Advisor
todd bailey
Posts: 22
Registered: ‎01-06-2010
Message 6 of 6 (3,174 Views)

Re: Enable No-Battery Write Cache

Of course any warranty on the controller baords is also voided,  but these cards have long since been out of production.

For a Business with an IT maint. budget, oem battery packs is the only way to go,  for the home user, with no budget,  I chose the more cost effective means to restore the controllers to working conditrion.

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