Solved Storage that is more resilient from powerloss

Which are more resilient to data corruption due to powerloss?

  • Hard Drives

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Vincent See

Member

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Hello Guys! I can't find any clear answer by searching google so I hope I can get advice from you, and advice would be great.

I know multiple external backups and a UPS is good practice from dataloss but between Hard Drives and Solid State Drives which is more resilient from data corruption due to powerloss.

They say Intel is the best and from Intel 320 series and above has "some" sort of powerloss protection as opposed to Intel Enterprise Drives that really offer it.

Between Hard drives and SSDs(Intel or Samsung) which is more resilient to data corruption? And if both SSD brands are just the same it would be better if I go to samsung because they are cheaper per GB.

Thank you!
 

kpa

Beastie's Twin

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Hard drives have mechanical moving parts and therefor are by nature much more suspect to damage on powerloss.
 

wblock@

Beastie Himself
Developer

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Both hard drives and SSDs can lose data if the power goes out. Hard drives have automatic head-parking mechanisms that provide some physical protection. SSDs have no physical heads to move, but still can have delays in writing data to flash. A few SSDs have relatively large capacitance to provide a clean shutdown on power loss. But neither hard drives nor SSDs can guarantee all data is safely written when the power goes out.

Fortunately, there is an easy solution to the problem: get a UPS. It is one of the cheaper forms of insurance.
 

ANOKNUSA

Aspiring Daemon

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How much planning have you put into this? While kpa is technically right, consider that (a) we got along well enough without SSDs for decades; and (b) it seems pretty stupid to throw money at an SSD to protect your data from power loss when you've already purchased a UPS for less money and now don't have to worry about power loss.
 

Murph

Well-Known Member

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Personally, I would say it's largely the same chance of problems with both traditional HDD and new SSD. Yes, the moving parts in a HDD can be an issue, but auto-parking more or less solved the problems on power loss sometime in the 1980s.

To me, the real issue is the data which is "in flight" at the time of power loss. The files which are half way through being written, the filesystem structures which are mid-update, etc. Modern filesystems mostly take care of their structural integrity via soft updates, journaling, etc; but that doesn't solve all problems down to the user data level.

If power loss is a frequent enough issue for you that you are regularly losing data, then you need to solve the power loss issues, not try to work around them through different storage types. Solve the major problem of frequent power loss (if you have one), then spec your storage devices based on their other characteristics and cost. Different device technology can never really fully help with the rug being pulled out underneath applications in the middle of them writing data.

Power loss should generally not be corrupting data on the drives themselves (other than perhaps the sectors being written precisely at the instant of failure, and the loss of pending writes in the write caches). The issues generally arise from just stopping things dead and having half-written updates from applications.

If you truly have a case where you need a higher tolerance of power failures, and can't properly address the issues using a UPS, the engineering to address that needs to go all the way up the application stack.
 
OP
Vincent See

Vincent See

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I have a FreeBSD Server set up at the office that needs to be shutdown every time we leave the office. Sometimes power outages happen, and most of the time we close the circuit breaker of the whole office and forgot to shutdown the server, other than buying a UPS(I will buy one sometime this year) thats why I want to get the most reliable consumer device if possible.. We are a small business hence the low cost choices that I mentioned...

Thank you for taking time to clarify my question I appreciate it :D
 

robroy

Active Member

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Vincent, in case you decide that a cheap UPS is better than no UPS, I'll share a recent experience. I bought an APC BE550G from B&H for $57.34, and I'm monitoring it with the apcupsd 3.14.13 package on 10.2-RELEASE amd64. The UPS attaches to the computer using a USB port. It worked on both computers I tried: an Intel DE3815TYKHE NUC (best avoided due to its poorly supported Realtek NIC), and a Supermicro 5017A-EF. A program included in the apcupsd package even allowed me to turn off the annoying UPS beeps, so the UPS keeps quiet when the power fails.

I was surprised by how well this cheap UPS worked with FreeBSD. In case you're curious, here's the apcaccess(8) output: apcaccess.txt.
 
OP
Vincent See

Vincent See

Member

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Messages: 73

Vincent, in case you decide that a cheap UPS is better than no UPS, I'll share a recent experience. I bought an APC BE550G from B&H for $57.34, and I'm monitoring it with the apcupsd 3.14.13 package on 10.2-RELEASE amd64. The UPS attaches to the computer using a USB port. It worked on both computers I tried: an Intel DE3815TYKHE NUC (best avoided due to its poorly supported Realtek NIC), and a Supermicro 5017A-EF. A program included in the apcupsd package even allowed me to turn off the annoying UPS beeps, so the UPS keeps quiet when the power fails.

I was surprised by how well this cheap UPS worked with FreeBSD. In case you're curious, here's the apcaccess(8) output: apcaccess.txt.

Hi robroy in case the UPS is low on power can it automatically tell the FreeBSD server to poweroff or APC does not have any software support for FreeBSD? Thats really cool if it does, thank you by the way for that info I learned something today :)
 

robroy

Active Member

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Hi robroy in case the UPS is low on power can it automatically tell the FreeBSD server to poweroff

Yeah, when the power has failed and the UPS is running the computer from its battery, sysutils/apcupsd will gracefully shut down FreeBSD when the remaining UPS power falls below a certain percent. It can also do the same when it forecasts that the UPS power will fail in under a configurable amount of time. For instance, it can tell FreeBSD to shut down once the battery level falls to 5%, or when the UPS becomes able to run the computer for only five more minutes--whichever comes first.

After sysutils/apcupsd tells FreeBSD to gracefully shut down, it tells the UPS to begin an unmanaged count-down period, after which the UPS puts itself in some kind of stand-by mode. The UPS shuts off its outlets when it enters this stand-by mode. The unmanaged count-down's necessary because when FreeBSD shuts down, apcupsd goes down with it; once apcupsd's no longer managing the UPS, the UPS has to enter stand-by on "auto-pilot." When the A/C comes back, the UPS returns power to its outlets and the computer can come back up automatically.
or APC does not have any software support for FreeBSD?

I'm not aware of any software that APC provides directly for FreeBSD, yet the integration that sysutils/apcupsd provides works well.
Thats really cool if it does, thank you by the way for that info I learned something today :)

You're welcome Friend.
 
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Vincent See

Vincent See

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Messages: 73

sysutils/apcupsd works with most APC UPSes. Although there was a time where APC had the idea of making their communications protocols proprietary, so look up the UPS model on http://www.apcupsd.org/ before buying one.

Yeah, when the power has failed and the UPS is running the computer from its battery, sysutils/apcupsd will gracefully shut down FreeBSD when the remaining UPS power falls below a certain percent. It can also do the same when it forecasts that the UPS power will fail in under a configurable amount of time. For instance, it can tell FreeBSD to shut down once the battery level falls to 5%, or when the UPS becomes able to run the computer for only five more minutes--whichever comes first.

After sysutils/apcupsd tells FreeBSD to gracefully shut down, it tells the UPS to begin an unmanaged count-down period, after which the UPS puts itself in some kind of stand-by mode. The UPS shuts off its outlets when it enters this stand-by mode. The unmanaged count-down's necessary because when FreeBSD shuts down, apcupsd goes down with it; once apcupsd's no longer managing the UPS, the UPS has to enter stand-by on "auto-pilot." When the A/C comes back, the UPS returns power to its outlets and the computer can come back up automatically.

I'm not aware of any software that APC provides directly for FreeBSD, yet the integration that sysutils/apcupsd provides works well.

You're welcome Friend.

Thank you wblock and robroy! I will buy a UPS and go for samsung for cheaper per GB. :)
 
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