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[dietmar]

I was reading all the posts about linux raid and i realice that the whole problem is about bateries to keep the cache write the disk in a power down situation, so I think from my ignorance : Are there exist any kind of batery to put to individual disks? or any way to do it ? this solve the whole problem about linux raid, we can use swraid with cache on, and the performance was ok. Sorry if my question have no sense.

You just invented the ultimate solution ;-) But AFAIK there is no such solution on the market. I guess newer RAID controllers will replace the battery by using flash memory cache (Adaptec SAS-5805Z). I also heard about disk using flash memory, but I do not know any vendor.

Also, I have no idea how SSDs behave. AFAIK they have large amounts of volatile RAM cache. Does anybody knows if/how that cache is protected against power loss?

 

[fromport]

You just invented the ultimate solution ;-) But AFAIK there is no such solution on the market. I guess newer RAID controllers will replace the battery by using flash memory cache (Adaptec SAS-5805Z). I also heard about disk using flash memory, but I do not know any vendor.

Also, I have no idea how SSDs behave. AFAIK they have large amounts of volatile RAM cache. Does anybody knows if/how that cache is protected against power loss?

I don't get the whole battery backup thingie.
Don't we all put our server on UPS'es these days ?
The real mission critical server have redundant powersupplies of which one i run one of the mains (protected by the building owener with a big generator set) and the other leg is on a big 120kva ups. The change of power going out is really minimal.

 

[lucho115]

I don't get the whole battery backup thingie.
Don't we all put our server on UPS'es these days ?
The real mission critical server have redundant powersupplies of which one i run one of the mains (protected by the building owener with a big generator set) and the other leg is on a big 120kva ups. The change of power going out is really minimal.

The motherboard could broken, or the cpu, etc.., in an homemade environment, use a 12v batery in pararell with the disks solve the problem, like old car stereos, jeje, i will try.
thks