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LunarMist

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Just like my other NSA units the write speed is always faster than the read speed. I never can understand the rationale for that. Regular drives always have faster reads than writes.
 

sdbardwick

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Just like my other NSA units the write speed is always faster than the read speed. I never can understand the rationale for that. Regular drives always have faster reads than writes.
B/c on writes, in some situations, you are limited by the interface to cache transfer rate, rather than the physical media transfer rate for reads. Depending on the number of drives, RAID implementation, and size of on-disk cache, you can maintain a higher write speed for an extended period of time.
 

LunarMist

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But why is the interface or other performance bottleneck asymmetrical in the opposite way from the conventional wisdom that reads are faster than writes?

The QNAP 10GbE card in the NAS is wired directly to the 10GbE Intel adapter in the computer, but I also tried a Quantia 10GbE adapter in the PC and there was no difference. I even tried the Quantia in the QNAP, but it is not recognizable and I'm not about to figure out how to add the drivers to the QTS. I also put the Intel 10GbE in the QNAP and that connects fine with the Quantia in the PC. The bottom line is that the performance is all the same.

I am using a simplified setup with RAID 6, EXT 4, no storage pools or Snapshots and no M.2 cache. The write speeds are sustained at 500-600, depending on the source. The OS cannot be caching anything, because it stayed about the same for over 14TB, when I terminated transfer manually. Read speeds are 400 or so.

The NAS and drives are quite cheap and literally twice as fast as the backup unit it will replace, so I'm not complaining.
I just want to understand the reason as it has been bugging me for several years. I don't think it is a coincidence since the behavior is the same with two QNAP and one Synology NAS, all being different models with different kinds of CPUs/chipsets.
 

LunarMist

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For some reason the QNAP take forever to boot. This one requires five minutes and announces the status in a synthetic female voice.
Synology units take about 1.5-2 minutes to boot. It's not a matter of CPU, just QNAP mentality. I'll probably leave the NAS on and live with the ~40W power drain.
 

DrunkenBastard

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Going to try out the Synology DS920+, on special on Prime day for $439. Will use 500 GB 970 Evo nvme drives for cache, and bump ram to 8GB.
 

Handruin

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That sounds like a decent setup for the money and nice that it has a cache option via nvme. What size HDDs will you be adding to it?
 

DrunkenBastard

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The Seagate Exos drives seem quite affordable (14TB for $285) but apparently they are third party via Amazon and a lot of people are getting serial numbers that come back as OEM.

The WD Gold 12 TB is $384.

i have three external 8TB WD enclosures I got a few years ago when they were on special for $129 or $179, I might just shuck them and go with three 8s to start. Also looks like RAM can be expanded to 20GB total with a 16GB so-dimm.
 

DrunkenBastard

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Ended up going with two WD 12TB easy store drives from Best Buy with store pickup. I dont like to expose them to UPS/Fedex handling.
 

DrunkenBastard

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So the way the cache works on the 920, with one nvme drive it is restricted to read cache, with two nvme drives it mirrors them and enables read and write caching. However you can't then mount them as a seperate drive. It can only be assigned as cache to a single specific volume. Hopefully DSM 7 will allow that in the future.

Basically silent running in terms of fan noise, drive seeks are the only sound it makes.
 

Handruin

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Sounds like they're playing it safe to reduce support calls with single-drive read caching. Bummer that it can only be used as a cache drive for a single volume.

I ended up picking up a pair of the WD Easystore 14TB drives that went on sale at Best Buy q couple days ago for $190. I'm debating shucking them or just leave them as additional USB backups. Do you use any specific utility to verify new drives? In the past I used HD Tune to run a sector test.
 

DrunkenBastard

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I just fill them with data then run a chkdsk. One of the three 12tb easy stores ended up giving me bad sector errors when initializing the SHR5, so now I test them for a couple days before shucking.
 

DrunkenBastard

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So I'm considering returning the 920+, and getting something that supports 10gbit Ethernet. I dont like the wait of 1 gbit for large transfers. However I cant tolerate any significant tiny fan noise from the associated switches.
 

Handruin

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What format do their 10Gb models use? Is it an sfp+ or rj45? Could you just run dedicated cable from your pc to the nas?

I'm still trying to figure out an adequate 10Gb config. There are some switches I've seen over at servethehome.com but to your point, they'll likely have some noise. It'll be in my basement so the noise is less of a concern. It's more the wattage usage.
 

Adcadet

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Long time since I've been around! Great to see conversations still going!

I too am moving to 10GB due to large file transfers. I have a detached garage with a single run of Cat6 where I have a Wifi access point, some POE cameras, and a TrueNAS Core box. I'm considering if I should replace the single run of Cat6 with fiber optic (multimode OC3?), both so I can send larger backups quicker but also to help minimize risk of a lightning strike taking out more equipment than it must. Anybody know about fiber optic and lightning?
 

Adcadet

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What do you guys use for your OS on FreeNAS/TrueNAS? A USB flash drive? Conventional 2.5" SSD? A SATADOM? The FreeNAS material used to strongly suggest a USB key (to avoid taking up an unnecessary SATA port, but ServeTheHome argues that USB flash drives may not be particularly reliable. Do you believe that performance of the disk holding the OS is largely irrelevant since most of the OS is just kept in RAM?
 

Handruin

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Long time since I've been around! Great to see conversations still going!

I too am moving to 10GB due to large file transfers. I have a detached garage with a single run of Cat6 where I have a Wifi access point, some POE cameras, and a TrueNAS Core box. I'm considering if I should replace the single run of Cat6 with fiber optic (multimode OC3?), both so I can send larger backups quicker but also to help minimize risk of a lightning strike taking out more equipment than it must. Anybody know about fiber optic and lightning?
Hey there

Running a fiber OC3 cable makes sense. I don't know for sure if they're all non-conductive but I suspect some might be. They're usually plastic, nylon, and glass for the most part. If you're going to pull a new cable, at least pull two. Do you know what you plan to use as a switch on both ends?

What do you guys use for your OS on FreeNAS/TrueNAS? A USB flash drive? Conventional 2.5" SSD? A SATADOM? The FreeNAS material used to strongly suggest a USB key (to avoid taking up an unnecessary SATA port, but ServeTheHome argues that USB flash drives may not be particularly reliable. Do you believe that performance of the disk holding the OS is largely irrelevant since most of the OS is just kept in RAM?
I just run Ubuntu Server 18.0.4 LTS on my NAS with the boot/OS drive being a SATA 1TB Samsung SSD. I would agree that the OS performance in relation to the OS drive is not any kind of significant factor for what I do with my NAS. It has 192GB RAM so lack of memory has never been an issue. Sometimes it's nicer to have a faster OS drive when performing OS maintenance and upgrades. They take less time.
 

Handruin

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I just fill them with data then run a chkdsk. One of the three 12tb easy stores ended up giving me bad sector errors when initializing the SHR5, so now I test them for a couple days before shucking.
I don't know if this will help, I was looking for a utility to write data to fill the drive like you were doing. I ended up finding a tip that recommended using the included windows command line utility called cypher.

e.g.
cipher /w:J:\test
  • First with fill all free space with zeros – 0x00
  • Second with all 255s, – 0xFF
  • Finally with random numbers

/W Removes data from available unused disk space on the entire
volume. If this option is chosen, all other options are ignored.
The directory specified can be anywhere in a local volume. If it
is a mount point or points to a directory in another volume, the
data on that volume will be removed.
 

time

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It's been 5 years since you were here. :eek: Good to see you visit, Adcadet. ;)

WRT lightning, don't forget the buildings are still sharing power, and therefore copper cable. If you are in a lightning-prone area, nothing short of a full lightning protection system upstream of your power box is going to help with a direct strike.

Having said that, the fiber solution is going to be way more reliable over time.

Don't know why Handy thinks you should pull two, they're not high frequency copper cables. If a rogue backhoe operator attacks, both will be toast anyway. Cable trauma seems unlikely in your situation with the PVC pipe, but maybe he's worried about the pre-terminations failing down the track?
 

Handruin

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It's less about backhoe cable trauma and more that if one is going through the hassle to pull a single cable, a second one is hardly much more effort. You never know if you'll need it for something and if by chance something is wrong with the cable you have the spare anyway.
 

time

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Yes, but does that conventional wisdom still make sense when applied to a fiber cable in a benign environment? I suppose it could be damaged during installation if someone went nuts with the bend radius.
 

Handruin

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I guess it doesn't. I have pulled tons of fiber cables in lab environments over the years. There has been a noteworthy amount of failures either due to trauma from pulling or defects in the terminated ends.

I've also seen plenty of times where the fiber cable was bent too far at the location of the switch or it being kinked in the cabinet door but those happen later over time. Probably not likely to happen in a home environment.
 
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