SSD Power loss protection?

[bgstcola]

I'm confused about power loss protection for SSDs.

I understand that real power loss protection are capacitors on the SSD.

Then I've read on this forum that Samsung use some kind of firmware level power loss protection that works well when the SSD is used in a normal desktop computer (not in raid). Is this correct and do all Samsung drives have this kind of power loss protection? I've read a lot of reviews for the Samsung 950 pro and most of them don't even mention power loss protection.

But what about other SSDs? Are they unprotected or do all modern SSDs have some kind of protection.

I don't know if I should consider power loss protection when I decide on my SSD setup? I don't wanna risk corrupting the file system in case of power loss.

 

[VirtualLarry]

A friend of mine, whom I had sold a PC, with an OCZ Vertex Plus R2 SSD, lost the SSD completely when the power glitched during a storm.

I would consider power-loss protection to be important, as important as TRIM support.

 

[Elixer]

I don't know if I should consider power loss protection when I decide on my SSD setup? I don't wanna risk corrupting the file system in case of power loss.

Well, then, your only option is to purchase a UPS so that don't happen.

 

[jkauff]

I've always used a UPS on my main computer, and it's saved my butt several times over the years. They're not that expensive, especially compared to the consequences of data loss. My favorite brand is CyberPower.

 

[CiPHER]

I understand that real power loss protection are capacitors on the SSD.

It depends on the terminology, but every SSD ought to have some kind of protection against FTL corruption, or the entire SSD will be 'bricked' resulting in total data loss and a non-functional drive which can only be resolved by perfoming a HPA secure erase procedure. Such a procedure wipes the mapping tables (FTL) and will reset the SSD back to factory conditions.

The FTL or mapping tables are crucial since they store what is on the SSD. If these become corrupted, or inconsistent with what is truly stored on the SSD, the SSD will show corruption or become bricked.

The only exception to this, are SSDs prior to the Intel X25-M such as MTron and MemoRight, which do not have an FTL to begin with. Without an FTL, there is no chance of FTL corruption because it does not exist. But the downside is that these SSDs are slower than HDDs in practice due to very slow random writes.

Then I've read on this forum that Samsung use some kind of firmware level power loss protection that works well when the SSD is used in a normal desktop computer (not in raid). Is this correct and do all Samsung drives have this kind of power loss protection?

That is correct according to my information. But i must stress that i do not work for any SSD company so i have to make due with public information. But it is well known the Samsungs use a technique known as 'journaling' to prevent their FTL from becoming corrupted. This means that upon unexpected power-loss, the SSD reverts to an earlier state. This violates the FLUSH CACHE command and as such Samsung SSDs are not suitable to be used in RAID configurations or other complex storage. At least not where data consistency is a concern.

But what about other SSDs? Are they unprotected or do all modern SSDs have some kind of protection.

Some consumer-grade SSDs have capacitors (Crucial MX100/MX200/M500/M550, Intel 320, S3500, S3700) but most do without. Some may use journaling and some are unprotected, which is why they fail more often.

I don't know if I should consider power loss protection when I decide on my SSD setup? I don't wanna risk corrupting the file system in case of power loss.

If data consistency is a concern for you, Intel is your best bet. Particularly the Intel 320 is the best and most reliable consumer-grade SSD ever produced. It can still be bought at some places, even though it is quite old. Crucial MX200 is my SSD of choice, since it sports DWA - a technique that allows the SSD to gain the performance benefits of SLC NAND instead of MLC NAND, as long as you do not fill the drive more than 50% of its capacity. Only the 250GB SATA version and the 250/500GB M.2 versions of the MX200 support this feature.

A friend of mine, whom I had sold a PC, with an OCZ Vertex Plus R2 SSD, lost the SSD completely when the power glitched during a storm.

That is normal for an OCZ SSD - some of their products had failure rates higher than 50%.

Well, then, your only option is to purchase a UPS so that don't happen.

That is a fallacy. With a UPS you are not protected. You are protected against power failures but you are not protected against unexpected power-loss. The difference is that all loss of power without a prior STANDBY IMMEDIATE command, counts as unexpected power-loss. This includes pressing the reset button, restarting from the BIOS, crashes/bluescreens and even tidy shutdowns are known to cause this by bad power-off timing.

You can read the SMART information and look for Unexpected Power-Loss. The raw value indicates the amount of times the SSD lost power prior to receiving a STANDBY IMMEDIATE command. This may be 40 or even 80 times for a casual desktop system. This does not mean such a user had 80 power failures. In western countries you have a power failure maybe once per every few years or so.

So the idea that a UPS makes capacitors or other form of power-loss protection superfluous, is simply not true.

 

[bgstcola]

Thanks CiPHER

I'm still puzzled why this isn't mentioned in reviews. In all the reviews I've read, if the SSD doesn't have capacitors, it is always considered to be without power losss protection. If I understand you correctly then any Samsung SSD will be as good as a SSD with capacitors as long as you use it as a single drive?

I've already decided to get an Intel 750 instead of a 950 pro as a system drive because I trust Intel more than Samsung.

I'm trying to decide if I should go with a 850 pro 2tb SSD or 2xMX200 1TB. I kinda want a single drive so I'm leaning towards the Samsung but if the MX200s are a safer choice I'd rather take them.

 

[CiPHER]

Thanks CiPHER

I'm still puzzled why this isn't mentioned in reviews. In all the reviews I've read, if the SSD doesn't have capacitors, it is always considered to be without power losss protection.

Well, Intel calls their capacitors 'Enhanced power-loss protection' where enhanced indicates it is an extra protection. This is technically more correct since without capacitors, you still need at least some sort of protection, or your SSD will be corrupted very easily, as happened frequently with previous generation SSDs (OCZ era).

If I understand you correctly then any Samsung SSD will be as good as a SSD with capacitors as long as you use it as a single drive?

No, a hardware protection in the form of capacitors is always better. Especially when paired with software protections. If there is only a software protection, this means the SSD would either be very slow or would violate the ATA spec by not honouring FLUSH commands, meaning anything but simple desktop storage is out of the question. Samsung would fall in the latter category as far as i know.

I've already decided to get an Intel 750 instead of a 950 pro as a system drive because I trust Intel more than Samsung.

If this is a simple Windows desktop, i question whether it makes all that much difference. The difference becomes relevant when you do special stuff. RAID arrays, ZFS, sLOG, SRT, and so on. Also SOHO/Enterprise i would not use consumer-grade stuff. Only the Intel 320 is suitable, but this was in the era where Intel did not have any special production line for enterprise-grade products so the Intel 320 was meant for both consumer/enterprise. That is why it is so great.

As for the Intel 750.. out of my head they did not have capacitors or there was confusion about this fact. I would double check. I don't have time right now, maybe tonight to check this.

I'm trying to decide if I should go with a 850 pro 2tb SSD or 2xMX200 1TB. I kinda want a single drive so I'm leaning towards the Samsung but if the MX200s are a safer choice I'd rather take them.

Well i think the differences are quite marginal. Intel, Samsung and Crucial (Micron) are major brands and if you stay with the big guys you get good products. There are differences, but they do not differ so much in my opinion. But Samsung is kind of cheating since they get to sell their cheap TLC products for the price of MLC products. And without capacitors, whereas Crucial sells MLC products with capacitors often for a slightly lower price than Samsung. That is one reason i tend to recommend Crucial over Samsung. But generally, once you buy their product, you are not going to notice any difference other than the fact Samsung benchmarks slightly better than Crucial.

In this era, the major SSD brands sell good products. It was only a couple of years ago that there was a major difference. OCZ was very popular but sold absolutely crap products, and their CEO was a criminal. Today, you have major players each with their own infrastructure (NAND + controller) and those without - the third party players that operate in the margin and use controllers like Phison, Silicon Motion, Sandforce, Toshiba, Jmicron and others. If you stay with the big guys (Intel, Samsung, Crucial/Micron) then all is well.

 

[Elixer]

That is a fallacy. With a UPS you are not protected. You are protected against power failures but you are not protected against unexpected power-loss.
...

So the idea that a UPS makes capacitors or other form of power-loss protection superfluous, is simply not true.

I never said a UPS would stop a firmware level disruption, however, it is aces for blackouts, brownouts, & over voltage or other power problems.
What you are talking about, is something that rarely happens these days.

So, you are going after the less than 1% of the time where conditions favor a firmware level disruption.

It was already pointed out in the other thread, yes, it would be better for all SSDs to have full protection, however, most consumer versions don't.
People vote with their wallet, and, it has been well established that worrying about this rare event is pretty much a non issue for the vast majority of the people.