Hp Proliant ML350 G6 - increasing performance

[ICTstudent]

hi all,

i'm currently using a Proliant ML350 G6 server as home for a couple of virtual machines.
and i have only one little issue

the performance this server delivers isn't really fast. and i heard some whispers that by the expansion of the battery this performance will increase. we currently have a 12MBps connection with the disks and want to improve this to as much as possible.

Thanks,

Wesley

[Michael A. McKenney]

RAID 10 over RAID 5 will help with performance. Parity writes can kill write performance on arrays.

Using VMWare, increase RAM and CPUs. Installing a battery cache will help with write caching. I would not do VM without a pair of quad cores and 64GB of RAM.

[Zygmunt Krawczyk]

>> Does de 512 MB cache module require a battery ? if it does, which one ?

for your ML350 G6 you need one of the two:

534916-B21 HP 512MB Flash Backed Write Cache
534562-B21 HP 1G Flash Backed Cache

These modules do not require a battery. They have super capacitors to provide power to flash write cache memory.

What is your processors and memory configuration?

[ICTstudent]

i'm so sorry, very good answer by the way ! Brilliant ! but i just had a meeting with the boss and he wishes BBWC.

can you give me those examples ? ( 1GB and 512 MB ) with batterys ??

Thanks a lot !

Wesley

[Zygmunt Krawczyk · Accepted solution]

>> i just had a meeting with the boss and he wishes BBWC.

BBWC is not good choice today. FBWC is new technology replacement for BBWC.
The same level of protection, even better. And with FBWC you do not have to replace battery every 3 year.

[ICTstudent]

i know i'm a pain in the @ss but..

just give me a little explanation.

Why is FBWC better then BBWC.
i had a huge discussion about this with my boss. and according to him BBWC saves/continues your processes when the power suddenly shuts off.
that's why we want BBWC but if you havesomething to add on this feel free to do it.

[Michael A. McKenney]

Flash based does not require a battery to store the data. It works like your camera SD/Compact Flash cards. So you don't need a battery like traditional cache memory.

My only concern is flash memory does have limited life span in number of writes. I have seen flash memory get corrupted and you never know when this happens.

Is it better than a battery cache? I don't think so. So you replace a battery every few years. It is better than corrupted flash memory that might hold SQL data?

[Zygmunt Krawczyk]

>> Why is FBWC better then BBWC?

"The HP flash-backed write-cache (FBWC) system offers important advantages over battery-backed write-cache (BBWC) systems. HP designed the FBWC with NAND1 flash devices so that power is not required to retain cache data. There is no longer a 48-hour battery life limitation and the data will be posted to the disk drive the next time you power up the server. HP has engineered the FBWC to function with long-life super-capacitors (Super-caps) instead of a battery. The Super-cap is only used to power the FBWC system during data backup. The result is that the FBWC retains cache data regardless of server power states and you can adjust maintenance and replacement schedules to accommodate the longer Super-cap lifecycle."

This cite is from
HP ISS Technology Update Volume 9, Number 2, page 2
http://h20000.www2.hp.com/bc/docs/support/SupportManual/c02231971/c02231971.pdf

I recommend reading this article, especially "FBWC architecture" section.

>> My only concern is flash memory does have limited life span in number of writes.

Remember, than cache memory module is not flash-based. Flash memory is used to backup
cache memmory in case of power loss. How many write cycles do you expect during life cycle
of the solution? Probably zero - if you have redundant power supplies and UPS.

[Michael A. McKenney]

The issue is when flash memory fails it does not always completely fail. You might get bit level failure on it. From and electrical engineering standpoint, I am not sure I would trust it. When you lose power to the drives and data is kept in it. How do we know its pristine and correct in the flash memory.

I had flash memory on my camera fail. Pictures were incomplete. The camera could not detect the failure. How does HP prevent this from corrupting data. If you have data from SQL in the flash memory, is it correct?

I tend to be conservative on technology advances. I know many who jumped on SSD drives in server storage and found it to be a major reliability issue.

[Zygmunt Krawczyk]

Michael,
I understand your point of view. But you need to see, that the latest HP SA P812 (the biggest SA controller) has FBWC only. Similar as MSA2000/P2000 array controllers have FBWC only. I believe that HP engineers know what they are doing.