Am I living too dangerously?

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LawrenceLee
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Am I living too dangerously?

Post by LawrenceLee »

All,

Have enjoyed this excellent software for about 1-1/2 years. However would like some advice as to how to best configure it best for performance and safety. Here's my system.

i7 10700
32GB RAM
250GB SSD C: Drive booting windows 10
8GB RAM dedicated as a L1 Storage cache space
500GB SSD with 420GB dedicated as a L2 Storage cache space (42GB allocated for TRIM operations)
4TB RAID1 WD Red D: HDD Drive data drive system.

Both the SSD boot drive and the 4TB HD raid share the same cache task. This task has Defer-Write of 10 sec enabled for the 4TB HDD.

Overtime the 500GB SSD L2 Storage cache space will be consumed to about 80% for cache with a cache hit rate on the D: drive consistently over 90%

The responsiveness and the benchmarking on my hard drive with this configuration is impressive as you will see in the attached screen grab. Reliability has not been in the issue so far.

1. Is the L2 caching space enabled with some sort of error correction in case of corruption?

2. Am I courting disaster by leaving my 4TB RAID1 WD Red D: Drive data drive system configured with a Defer-Write of 10 sec?

3. I have no UPS attached to my system but could get one. I'd prefer not though. I don't want to breathe lead vapor from a so called "sealed lead acid" battery in a UPS near my computer. Would the software be triggered to write its L2 contents on power loss by a UPS?

Thanks in advance for your advice on this.
2021-05-01 04_47_23-PrimoCache screen 1.jpg
2021-05-01 04_47_23-PrimoCache screen 1.jpg (142.28 KiB) Viewed 1633 times
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2021-05-01 04_47_23-PrimoCache screen 2.jpg (66.71 KiB) Viewed 1633 times
2021-05-01 04_43_05-CrystalDiskMark 8.0.1 x64 (UWP).jpg
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Jaga
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Re: Am I living too dangerously?

Post by Jaga »

LawrenceLee wrote: Sat May 01, 2021 11:45 am1. Is the L2 caching space enabled with some sort of error correction in case of corruption?
Not that I am aware of. ECC would only come into play if you had for example, true ECC RAM that the L1 was setup on. Primocache is primarily meant for blazing speed without all the error correction algorithms mucking it up. With that in mind, any machine you use it on should be rock-solid to begin with. Highly overclocked machines or those with power problems, weak components, etc.. should probably stay away from any type of write caching.

LawrenceLee wrote: Sat May 01, 2021 11:45 am2. Am I courting disaster by leaving my 4TB RAID1 WD Red D: Drive data drive system configured with a Defer-Write of 10 sec?
My personal opinion is: yes. I had house power drop out twice just yesterday (a rare occurrence even in the last 10 years), and had I not had a UPS on this machine, I would have risked data loss/corruption, even though the workstation in question truly is rock-solid. Without a UPS, I'd suggest dropping deferred write time to 5 seconds or less. And even then you're risking data.

LawrenceLee wrote: Sat May 01, 2021 11:45 am3. I have no UPS attached to my system but could get one. I'd prefer not though. I don't want to breathe lead vapor from a so called "sealed lead acid" battery in a UPS near my computer. Would the software be triggered to write its L2 contents on power loss by a UPS?
Nope. On power loss, any queued writes that haven't actually hit the drive yet are lost (or RAM in the case of a L1). Primcache has recently (latest major patch I think?) had a L2 cache validation routine added on startup. I don't personally use a L2 however, so don't quote me on whether or not it is in yet.

Today's UPS units are fairly good in terms of being sealed - I've had one sitting not three feet from me (with dual batteries) for around 7 years now, no adverse effects I can detect. And I have new-ish replacement batteries for it sitting across the room. No funny smells or liquid at all. I think it's pretty much a non-issue, as long as you get a good brand-name unit to use.

As far as triggering Primocache to flush writes on a power loss where a UPS is connected, that's absolutely possible. You simply tell the UPS's software to do a graceful shutdown after X minutes, or when the battery drains to X% level. The UPS software then tells WIndows to shut down without question, at which point Primocache is told to "finish up, the system is coming down immediately", and it flushes all pending writes. Need a decent UPS with a USB connection (or add-in card) to get that functionality.
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Re: Am I living too dangerously?

Post by Support »

LawrenceLee wrote: Sat May 01, 2021 11:45 am 3. I have no UPS attached to my system but could get one. I'd prefer not though. I don't want to breathe lead vapor from a so called "sealed lead acid" battery in a UPS near my computer. Would the software be triggered to write its L2 contents on power loss by a UPS?
currently no. Please note that system crash/freeze or other ungraceful shutdowns, in addition to power loss, also might cause data loss because PrimoCache has no chance to flush deferred write data during such scenarios.
InquiringMind
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Re: Am I living too dangerously?

Post by InquiringMind »

LawrenceLee wrote: Sat May 01, 2021 11:45 am ...However would like some advice as to how to best configure it best for performance and safety...Both the SSD boot drive and the 4TB HD raid share the same cache task. This task has Defer-Write of 10 sec enabled for the 4TB HDD.
If you are using L1 and L2 caching, then you should consider separate cache tasks for the SSD and HDD - the HDD will benefit from L2 caching while your SSD will not (in fact, L2 will likely slow things down, though not by a perceptible amount). I would suggest separate cache tasks with L1 caching only on the SSD and L1+L2 on the HDD.
LawrenceLee wrote: Sat May 01, 2021 11:45 am 2. Am I courting disaster by leaving my 4TB RAID1 WD Red D: Drive data drive system configured with a Defer-Write of 10 sec?
Backups are your first line of defence here, and if you aren't backing up regularly, you court disaster whatever your setup. You need to have full image backups (that is, a complete copy of your disk) made onto another HDD (to cover the inevitable event of your current HDD failing). Windows' own backup may suffice here but Macrium Reflect is a widely-recommended, free alternative (I use Drive Snapshot myself which isn't free, but is very lean and efficient).

In addition, ensure that your most important (and frequently updated) files are automatically backed up, again onto a separate disk. File versioning software (which keeps multiple copies of each file as it changes, allowing you to recover previous versions if needed) would be best here. My recommendation here would be Aphar Backup (webpage is Dutch but the program runs in English) since again, it is free, lean and simple (and doesn't rely on third-party infrastructure like .NET Framework) but other options include AutoVer, Yadis Backup (both free) or FileHamster (commercial).

When setting these up, the contents of your Documents folder should be an obvious choice but also include your %APPDATA% and %USERPROFILE% folders since these will contain program configuration files.
LawrenceLee wrote: Sat May 01, 2021 11:45 am 3. I have no UPS attached to my system but could get one. I'd prefer not though. I don't want to breathe lead vapor from a so called "sealed lead acid" battery in a UPS near my computer. Would the software be triggered to write its L2 contents on power loss by a UPS?
Lead-acid batteries do not give off lead vapour - small amounts of hydrogen gas can be produced when charging but this should not be a health risk unless you are using them in a sealed room. For more information on potential hazards, see Concordia University Environmental Health and Safety - Lead Acid Batteries (1.3MB PDF file) - section 3 deals with sealed lead acid batteries. However it is probably not worth considering a UPS unless your power supply is unreliable.

I have experienced a couple of power outages recently (due to maintenance work) and did notice some files (specifically configuration files held open by programs running in the background) had been corrupted (either partially or fully set to null characters, which resulted in some strange behaviour with one program, CoreTemp). However restoring from backups fixed that issue.
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