HPE Smart Storage Battery for HPE Smart Array P440/4G Controller.

[parnassus]

Hello all,

In reading the latest HPE Smart Array P440 Controller QuickSpecs (August 2016, here) I noticed that the HPE Smart Array P440/4G Controller option kit (726821-B21) - with respect to the other possible HPE Smart Array P440/2G Controller option kit (820834-B21) - doesn't include the HPE Smart Storage Battery (727258-B21) which acts as the backup power source necessary to protect the Controller data on its Flash-backed Write Cache).

A note in that QuickSpecs says:

"HPE Smart Array P440/4GB FBWC controller option kit does not include the HPE Smart Storage Battery the backup power source necessary to protect the data on the Flash-backed Write Cache. HPE Smart Storage Battery is an item that has to be purchased separately if this is the first P-series Smart Array controller on your Gen9 server."

My question is about sentencing: that "...is an item that has to be purchased if..." means that the presence of the HPE Smart Storage Battery is mandatory for the (first/single) HPE Smart Array P440/4G Controller option kit (726821-B21) to work or just that it's only highly recommended but not mandatory?

In other terms: Can the HPE Smart Array P440/4G Controller option kit (726821-B21) work without the HPE Smart Storage Battery (727258-B21) installed?

If "Yes, it can" is the answer...can I add the HPE Smart Storage Battery (727258-B21) at later time (provided that this later addition will require an adequate Server maintenance window)?

Thanks!

[Torsten.]

The controller needs the battery in order to use the write cache safely.

The Gen9 server series need only a single battery for multiple controllers, older controllers need an own battery each.

[parnassus]

Hello Torsten, thanks for answering.

I still have a doubt: if the HPE Smart Array P440/4G doesn't find the HPE Smart Storage Battery properly fitted...will it work "normally" (with the Write Cache disabled and lowered performance) or will it not work at all?

That's the point for me, I mean: I can survive for a week or so with the Write Cache disabled and a Smart Array Controller working (consider that, in meantime, I have a very good UPS protecting the Server)...instead...I really can't survive with a non functioning Smart Array Controller due to the - temporarily - lack of that battery option.

I need to understand that (I know the benefits of having the HPE Smart Storage Battery fitted).

Thanks!

[Jimmy Vance]

---

@parnassus wrote:

Hello all,

In reading the latest HPE Smart Array P440 Controller QuickSpecs (August 2016, here) I noticed that the HPE Smart Array P440/4G Controller option kit (726821-B21) - with respect to the other possible HPE Smart Array P440/2G Controller option kit (820834-B21) - doesn't include the HPE Smart Storage Battery (727258-B21) which acts as the backup power source necessary to protect the Controller data on its Flash-backed Write Cache).

A note in that QuickSpecs says:

"HPE Smart Array P440/4GB FBWC controller option kit does not include the HPE Smart Storage Battery the backup power source necessary to protect the data on the Flash-backed Write Cache. HPE Smart Storage Battery is an item that has to be purchased separately if this is the first P-series Smart Array controller on your Gen9 server."

My question is about sentencing: that "...is an item that has to be purchased if..." means that the presence of the HPE Smart Storage Battery is mandatory for the (first/single) HPE Smart Array P440/4G Controller option kit (726821-B21) to work or just that it's only highly recommended but not mandatory?

In other terms: Can the HPE Smart Array P440/4G Controller option kit (726821-B21) work without the HPE Smart Storage Battery (727258-B21) installed?

If "Yes, it can" is the answer...can I add the HPE Smart Storage Battery (727258-B21) at later time (provided that this later addition will require an adequate Server maintenance window)?

Thanks!

---

Any Smart Array controller with a cache module requires the smart storage battery.  For Gen9 one battery can work with several controllers. Previous generations of servers required a seperate battery for each controller. Without the battery performance will suffer, and if I recall correctly you can only create RAID levels 0 and 1 without having a working battery in the system.

[Torsten.]

The battery is an option, hence the controller works without.

In case of a power failure the battery delivers power to the controller, so the controller can write the cache contents to a special flash memory to save the data. Without battery no write cache, because data may be lost in case of power failure.

[parnassus]

OK, that sounds a little more reasonable to me. Thanks Torsten!

Last question...since you cited the Smart Array RAID 0/1 creation restriction in case the HPE Smart Cache Battery is not fitted...can you confirm that?

Is there a document that will explain what are the operating restrictions (temporary or definitive) for a Smart Array Controller initially operated without its Smart Cache Battery?

The fact that I will not be able to create a RAID 6 Volume if the battery is not equipped could be a real (deployment) stopper to me...so I will be forced to wait for the battery to arrive before setting up the whole Server.

[Torsten.]

From the quickspec you already know:

4 GiBytes Flash Backed Write Cache (FBWC) or 4 GiBytes Flash Backed Write Cache kit with Battery (FBWC) provides read ahead caching and write back caching with indefinite write cache data retention in the case of unexpected power outage

...

Standard on the P440 are RAID 6, RAID 60, RAID 1 ADM, Capacity Expansion, mirror split, recombine, and rollback in Online Mode, Drive Erase, Performance Optimization-Degraded Reads and Read Coalescing, Move/Delete any individual LUNS

[Jimmy Vance]

Buy a battery, it is not "optional"

---

@parnassus wrote:

"HPE Smart Storage Battery is an item that has to be purchased separately if this is the first P-series Smart Array controller on your Gen9 server."

My question is about sentencing: that "...is an item that has to be purchased if..." means that the presence of the HPE Smart Storage Battery is mandatory for the (first/single) HPE Smart Array P440/4G Controller option kit (726821-B21) to work or just that it's only highly recommended but not mandatory?

---

Your original question didn't include the entire sentence.  "is an item that has to be purchased separately if this is the first P-series Smart Array controller on your Gen9 server."

The battery isn't an option, it is a required part for the proper operation of the smart array controller. Since Gen9 can share the battery amongst several controllers you only need to purchase one if a "P" series controller was not included in the original SKU. Will a controller function without a battery, yes it will, but not fully functional as it isn't designed to work without one.

[parnassus]

Sorry Torsten...I'm an old school guy...I don't want to be too pedantic but a clarification is necessary: yes, I already know what QuickSpecs document states and I already know that performance degradation should be expected when no HPE Smart Storage Battery is present...that's not the point...what I don't know now is if there could be Smart Array Controller functionality restrictions/limitations when no FWBC is present (you wrote that you probably recall something about that possibility).

The point is...since you said that Smart Array Controller may be limited in creating only RAID 0/1 Volumes when not equipped with HPE Smart Storage Battery instead of offering its whole RAID levels capabilities (RAID 0, 1, 10, 5, 50, 6, 60 and 10 ADM) when the HPE Smart Storage Battery is present...I asked for a possible clarification but the answer you gave sounded a little bit murky (unclear) to me.

Sorry for that.

For sure, re-reading the QuickSpecs, a statement shows up:

"It features eight internal physical links and delivers increased server uptime by providing advanced storage functionality, including online RAID level migration between any RAID levels with flash-backed write cache (FBWC), global online spare, and pre-failure warnings"

so, at this point, for sure the Online RAID level migration functionality requires the FBWC presence but doesn't say nothing about the absence of the HPE Smart Storage Battery.

[parnassus]

Thanks Jimmy

No no...I reported the whole sentence (see above)...what I asked - referring to sentencing about a part of that whole sentence - is about the fact that HPE didn't wrote explicitly "You must purchase and install the HPE Smart Storage Battery..." (independently that that Controller is the first one or not) but wrote instead "HPE Smart Storage Battery is an item that has to be purchased separately..."...giving the user two possible alternatives...using the HPE Smart Storage Battery (thing I want to do) and not using the HPE Smart Storage Battery (thing I probably will be forced to do for some time during deployment)...these are two very different things IMHO.

Since I'm not English mother tongue...I ask: is the "it has to..." equal to "it must..."? great doubt.

HPE Documentation left the user arguing if the HPE Smart Storage Battery option is (really) essential or not and if the HPE Smart Array P440/4G Controller functionalities (not its performances!) shall be impaired heavily or not for the absence of that battery.

It's not a matter of not purchasing a few bucks option...it's a matter of be clear and simple.

That QS doesn't say practically nothing about that.

Very vague IMHO.

P.S.

OT start

I found interesting that the P440/2G has the HPE Smart Storage Battery option included while the P440/4G has not!

That's the Intricacy Office sign...isn't it?

OT end