@black3dynamite said in What flavor of linux to replace windows?:

Choosing .NET Core or .NET Framework depends on your need.
https://docs.microsoft.com/en-us/dotnet/standard/choosing-core-framework-server

Summary.... .NET Core when you are a competent developer. .NET Framework when you are using legacy crap that you can't get away from.

They make it pretty clear which is first class and which is a crippled fallback.

@Donahue said in Adding tape drive:

at this point, I would have to get management buy in to really consider cloud, I want to evaluate the options before hand to know how much I should or shouldn't be pushing for the cloud. Recent conversations with @scottalanmiller have me questioning our historical reasons and motivations for why we use what we use. In my case, we have a mix of prior misinformed speculation and my limited personal experience.

I don't see a reason to emulate tape if I'm not going to use tape, but I really don't know

Well if you use tape, then no reason to emulate.

Well, there was nothing in the 24 hour test. I have started another one for 7 days, which is the longest option in the current version.

@Dashrender said in Large or small Raid 5 with SSD:

@scottalanmiller said in Large or small Raid 5 with SSD:

@Donahue said in Large or small Raid 5 with SSD:

@scottalanmiller said in Large or small Raid 5 with SSD:

@Donahue said in Large or small Raid 5 with SSD:

@scottalanmiller said in Large or small Raid 5 with SSD:

@Donahue said in Large or small Raid 5 with SSD:

$411

Good for what it is. Still a bit of money.

I was under the impression that OBR was the way this should be done.

OBR probably makes sense at $411 to get around it 🙂

I can’t tell if you are for it or against it, and what ‘it’ is

$411 to get around putting everything in an OBR. If non-OBR was "free" we'd prefer it. Extra capacity, extra channels, that sort of thing. But it isn't free, it costs money. If it was $1 or $5, we'd basically always do it. But at $411, that's pretty steep. That is more than buying two SSDs on your own and doing it. So really doesn't make sense when just doing two small SSDs in RAID 1 isn't normally a good idea.

What enterprise SSDs are you buying where you get two for under $411?

No value in enterprise SSDs for a RAID 1 boot storage.

@scottalanmiller said in Battery Backup with SSD raid:

@pete-s said in Battery Backup with SSD raid:

@scottalanmiller said in Battery Backup with SSD raid:

@pete-s said in Battery Backup with SSD raid:

@scottalanmiller said in Battery Backup with SSD raid:

SSD NV protection is to allow the SSD's cache to flush safely should power be lost. RAID NV / battery protection is to allow the RAID's cache to flush safely should power be lost. Each is important on its own, neither covers for the other one.

That's technically slightly incorrect.

The non-volatile cache memory on the raid controller is to be preserve the data that has not yet been written to the drives, until power is restored again.

On the SSD the capacitors hold enough charge so that the drive can write the remaining data in the cache memory to the actual flash memory after the power is gone. The cache is DRAM so it will loose it's contents after a few seconds.

The only time details like this matter is if you remove the battery from a raid card, your data might be lost.

I'm missing how that is different than what I said. What you said is correct, but I feel like you just reworded what I said, with the added detail that the RAID card flush is not until power is restored, which one hopes is obvious.

Sorry Scott, you're right. I was just thrown off by you said "SSD NV protection" and because you worded both thing the same. Obviously both things are to protect from data loss at power failures.

OIC, you are saying that the SSD is volatile, but has a battery in most cases? makes sense.

Almost, let me explain. Below is a picture of an Samsung enterprise SSD, SM863.

The SSD controller (yellow) is the brain. The flash memory (green cross) is non-volatile so it will not suffer data loss without power. There are also more flash memory on the backside.

The cache memory however is the blue ring and it will lose it's memory as soon as the power is removed. It's the same type as the memory in your computer, DRAM. That would cause immediate data loss and that is not good and that is why enterprise drives have a lot of capacitors (red circles).

The capacitors (red) act like small rechargeable batteries. When the drive loses it's external power these small capacitors will work as a reserve power for the entire drive. The controller (yellow) knows that it has lost external power so it will quickly write the data from the cache memory (blue) to the flash memory (green) before the reserve power from the capacitors (red) are empty. That way data loss is prevented. This will only take a couple of seconds at most.

0_1538765396271_samsung_ssd.png