Raid 0 Performance

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dmyze
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Raid 0 Performance

Post by dmyze » Thu Sep 12, 2019 12:35 am

So when I bought my QNAP TS-873-8G-US my original plan was to fill it up with a RAID 10 array.

8 drives in two raid 0 arrays.

Now that I'm getting it set up, I'm starting to wonder how much I can fill my need for speed.

My first thought was to instead of two equal raid 0 arrays set one array at 6 drives and another with two drives, have the smaller array with bigger drives and then set up a backup job.

But then my thoughts got even greedier, I do have enough bays on my other PC (4) to set up a backup location.

I've read online that the performance difference between raid 0 with 6 drives and raid 0 with 8 drives is dependent on your RAID controller.

So what do you guys think, would i see much of an improvement if I went with all 8 bays in a RAID 0?

All I really care about is read speed as I have a 500GB SSD for write caching. (EVO 970)

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Trexx
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Re: Raid 0 Performance

Post by Trexx » Thu Sep 12, 2019 2:12 am

1) Don't mess with Raid-0 unless you don't care about any of your data or hours lost rebuilding systems due to a single drive failure.
2) Don't mess with Write caching unless you have (2) SSD's running in a Raid-1 config. SSD's fail/wear-out and you will have no advanced warning
3) Create a single Raid-6 group with 8 Drives (which are on QNAP's compatibility list) + a UPS for power stability and call it a day.

Unless you have 10GbE networking, it likely won't matter anyway. But since you haven't mentioned what you are going to use this for, see items 1-3 :)
Paul

Model: TS-877-1600 FW: 4.4.1.x
QTier (HDD): [RAID-5] 6 x 3TB HGST DeskStar NAS QTier (SSD): [RAID-1] 2 x 1TB WD Blue m.2's
(SSD): [RAID-1] 2 x 500GB Evo 860
RAM: Kingston HyperX Fury 64GB DDR4-2666
GPU: EVGA GTX 1060, ACX 2.0(1 Fan), 6GB
UPS: CyberPower AVR1350 Ext. Backup: USB 3.0 Seagate 5TB
Media Boxes: Nvidia ShieldTV Pro, AppleTV 4k, Various Roku's

Model: TVS-673 32GB FW: 4.4.1.x Test/Backup Box
-----------------------------------------------------------------------------------------------------------------------------------------
NAS RAID Rebuild Times | Live QTS Videos | | QNAP NAS Guide | Information needed when you ask for HELP | QNAP Links, Tutorials, etc.
2018 Plex NAS Compatibility Guide | QNAP Plex FAQ | Moogle's QNAP Faq

dmyze
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Re: Raid 0 Performance

Post by dmyze » Thu Sep 12, 2019 2:17 am

Yeah I already have a 10gbe Network, and I have an old Drobo which I already back everything up onto, and I have another windows server with 4 bays that I can backup onto as well.

I'm ok with one disk failing, I can restore from my drobo / windows server / and I also have tape backups set up as well although I'd hate to restore from them.

What I want is when I'm running to the airport, and I suddenly realize I forgot some large set of files, that I can copy it off my share onto my travel USB SSD without missing my fight.

(and I want all my efforts of setting up a 10gbe to actually pay off somehow...)

I'm also not worried about the write-cache failing, as long as I just have to re-start the file transfer whenever that happens. My old RAID has a 4GB ram write cache and SSD write cache that I never had any issues with. That server is just so old, so I deiced to upgrade to something (physically) smaller.

Here is what is says on stackoverflow:

https://serverfault.com/questions/69485 ... erformance
Last edited by dmyze on Fri Sep 13, 2019 2:37 am, edited 1 time in total.

dmyze
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Re: Raid 0 Performance

Post by dmyze » Thu Sep 12, 2019 10:00 am

After thinking about it, I'm going to do 4 drives in Raid Zero on my one server and 5 drives in Raid 0 on my QNAS. When I run out if space I'll add bigger drives to the windows server and add more drives to the QNAS. I'll see how long it takes to copy with the two arrays and 10gbe.

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Trexx
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Raid 0 Performance

Post by Trexx » Thu Sep 12, 2019 10:52 pm

Just realize that the Qnap OS, apps, etc. beside your data live on those drives so when one goes bad, you lose the entire system basically.

My time is worth more to me than the cost of 1 drive to at least run raid-5.

Also the USB port speed will have a bigger perf impact than raid in your prior example.

Sent from my iPhone using Tapatalk
Paul

Model: TS-877-1600 FW: 4.4.1.x
QTier (HDD): [RAID-5] 6 x 3TB HGST DeskStar NAS QTier (SSD): [RAID-1] 2 x 1TB WD Blue m.2's
(SSD): [RAID-1] 2 x 500GB Evo 860
RAM: Kingston HyperX Fury 64GB DDR4-2666
GPU: EVGA GTX 1060, ACX 2.0(1 Fan), 6GB
UPS: CyberPower AVR1350 Ext. Backup: USB 3.0 Seagate 5TB
Media Boxes: Nvidia ShieldTV Pro, AppleTV 4k, Various Roku's

Model: TVS-673 32GB FW: 4.4.1.x Test/Backup Box
-----------------------------------------------------------------------------------------------------------------------------------------
NAS RAID Rebuild Times | Live QTS Videos | | QNAP NAS Guide | Information needed when you ask for HELP | QNAP Links, Tutorials, etc.
2018 Plex NAS Compatibility Guide | QNAP Plex FAQ | Moogle's QNAP Faq

dmyze
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Re: Raid 0 Performance

Post by dmyze » Fri Sep 13, 2019 2:03 am

Yeah I'll see how things go, but my underling question is still out there, is their performance increase in using RAID 0 with 5 drives vs 6 drives vs 8 drives.

I understand that theoretically each drive adds speed, but I've seen a few websites that say after around 6 drives you start getting bottle necked by your RAID controller.

If I go the 5 drive route as I'm thinking now then I can put in something for the other bay for the system stuff until I upgrade.

I want to make this this thing as fast as possible to really take advantage of my 10gbe network.

I don't see how hooking up via USB would be any faster when the bottle neck is the hard drive read speed.

Here is what it says on stackexchange:

https://serverfault.com/questions/69485 ... erformance

Bob Zelin
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Re: Raid 0 Performance

Post by Bob Zelin » Fri Sep 13, 2019 7:00 am

Hi dmyze -
I think because people like me have a lot of experience (and so does Trexx) - when I see questions like this - I say "are you kidding me" -
but I did not respond until I wehn to your link on Stack Exchange.

Is there a performance difference between a RAID with 2 drives and with 16 drives ? OF COURSE THERE IS, but if you have no experience in doing so, then you just don't know.
I had a gentlemen contact me from India, who simply could not understand why he was getting such poor performance from his QNAP over a 10G network, while using only one SSD drive.
I think I wound up "insulting him" because he felt he was very knowlegable about all of this, and could not understand why he needed to use multiple SSD's in a RAID group to get good performance for his
workgroup. Needless to say - he never wound up hiring me. I guess I was rude, because I could not give him a sufficient answer on why one single SSD could not be enough for his entire workgroup with his QNAP.

Bottom line - stop reading all this stuff on line. (I feel like this is me, when I go to my doctors office, and try to tell him what medicine works, and does not work, based on what I read on the internet).
I don't know what your application is, but if you put EIGHT drives in a DECENT QNAP model (no Annapurna models - I don't care what QNAP says or shows on their website) - you will get great performance ovver 10G, be it RAID 0, RAID 5 or RAID 6.

With eight 7200 RPM drives on a model like the TVS-872XT, you will get over 800 MB/sec with a 10G connection. With the same drives, in a QNAP TS-832X, you will barely get 200 MB/sec with the same computer, and the same RAID configuration. How do I know this ? I do this every day.

Bob Zelin
Bob Zelin / Rescue 1, Inc.
http://www.bobzelin.com

janwer
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Re: Raid 0 Performance

Post by janwer » Sat Sep 14, 2019 1:53 pm

For 8-th bay NAS I would use it in one of three ways:
1. Two SSD in RAID1 for OS and apps only. Six HDD in RAID5 for data. This way you have the protection, speed and performance. RAID0 is delayed waste of many hours or days time for recreating everything. RAID6 is unnecessary waste of disk space and CPU power without substantial increase of availability or protecting. RAID6 rebuild time is long and it takes more CPU power to write. Better have backups. This setup I use and it's fast for Roon database and Plex video files.
2. Eight HDD in RAID5. This way you don't have the speed with databases and small files but it's faster for large amount of data and the best way to saturate 10Gbps.
3. If you like to live your life fast and dangerously use one SSD for system volume and apps and seven HDD for data in RAID0. Have daily backup of everything. I don't know if you can backup whole partition with system files? Maybe taking discs out and make image of whole drive?

SSD will add speed only in specific scenario like database or web server. It's useless for large files like few TB video library - fastest will be RAID0 and RAID5 second.
TVS-951x TS-431P2 Unraid

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Re: Raid 0 Performance

Post by dolbyman » Sat Sep 14, 2019 2:04 pm

i disagree thar raid6 is a waste of cpu and space

cpu power for parity calc is easily spared nowadays.. and the extra parity has saved a few people in this forum over the years (those without full backups)

janwer
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Re: Raid 0 Performance

Post by janwer » Sat Sep 14, 2019 5:31 pm

Are there still people without backup? Really?
Don't you think there is serious flaw in this reasoning?

If one has backup then after disk fail first just do another fresh backup. Rebuild array is done after backup. No problem.
Wasting precious disk space on RAID6 and "saving" on backup?
TVS-951x TS-431P2 Unraid

dmyze
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Re: Raid 0 Performance

Post by dmyze » Mon Sep 23, 2019 9:59 pm

I ended up setting up a 8 drive raid 10 array. I was able to speed up the rebuild by tweaking things in the SSH, following various posts from here. I got all my data transferred over (about 15 TB) in a few days by (after testing a number of methods) using FTP. My server has 4 bays that I am putting 3 12 TB drives in a raid 5 configuration to be the primary backup/fail-over. And I managed to salvage my Drobo and will use it as cold storage. So I think my data is safe. (plus I also have an 8 bay LTO, that I have backed everything up onto tape as well)

I did discover in this process that 3 of my drives are 5200 RPM, and so i have ordered 3 more drives that match the rest of the 7200 RPM drives. So at this moment I am slowed down by those drives.

I haven't installed the Cache module yet, only because the module I bought is not compatible with my device. I bought a new 10 gbe card with the right kind of SSD connection from QNAP and will install that soon.

I did some testing already copying a 17 GB file back and forth. In theory a raid 10 with 8 drives should give me 8x read and 4x write. But so far in practice I seem to be hitting a 3 gbe cap when reading data, and a 4 gbe cap when writing data. Not sure if it's a configuration issue yet, will test it some more once I get the better drives.

Edit: Just remembered, I ran out of 10Gbe connections on my switch so my desktop PC is only on a 5gbe connection which is skewing this test result.

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storageman
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Re: Raid 0 Performance

Post by storageman » Mon Sep 23, 2019 11:48 pm

dmyze wrote:
Mon Sep 23, 2019 9:59 pm
I ended up setting up a 8 drive raid 10 array. I was able to speed up the rebuild by tweaking things in the SSH, following various posts from here. I got all my data transferred over (about 15 TB) in a few days by (after testing a number of methods) using FTP. My server has 4 bays that I am putting 3 12 TB drives in a raid 5 configuration to be the primary backup/fail-over. And I managed to salvage my Drobo and will use it as cold storage. So I think my data is safe. (plus I also have an 8 bay LTO, that I have backed everything up onto tape as well)

I did discover in this process that 3 of my drives are 5200 RPM, and so i have ordered 3 more drives that match the rest of the 7200 RPM drives. So at this moment I am slowed down by those drives.

I haven't installed the Cache module yet, only because the module I bought is not compatible with my device. I bought a new 10 gbe card with the right kind of SSD connection from QNAP and will install that soon.

I did some testing already copying a 17 GB file back and forth. In theory a raid 10 with 8 drives should give me 8x read and 4x write. But so far in practice I seem to be hitting a 3 gbe cap when reading data, and a 4 gbe cap when writing data. Not sure if it's a configuration issue yet, will test it some more once I get the better drives.

Edit: Just remembered, I ran out of 10Gbe connections on my switch so my desktop PC is only on a 5gbe connection which is skewing this test result.
You will get better sequential performance with RAID 5/6 than RAID 10.
These boxes prefer writing parity to mirroring files - trust me.
Only use RAID 10 if IOPs is No 1 priority.

dmyze
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Re: Raid 0 Performance

Post by dmyze » Tue Sep 24, 2019 3:16 am

Yeah I'm doing RAID 10 because I want to have blazing fast reads.

I switched my destkop over to the 10gbe port. I tested using FTP reading and writing the same 17GB file again.

I'm happy with the speeds, but I find it odd that the write speed is still faster then the read speed. I am seeing just under 5 gb/s when writing to the array, and it seems to hit a physical cap at 3 gb/s when reading data. (as it stops right at 3 and doesn't go any faster)

my pc has a EVO 960 1 TB drive that is rated beyond anything that 10gbe can do. I'd be happy to believe that 5gb/s is the fastest the drives can just handle. But why is the writing 2 gb/s faster?

dmyze
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Re: Raid 0 Performance

Post by dmyze » Tue Sep 24, 2019 3:34 am

Looking at my system resources I see it says there is a 5 GB cache in memory, so it must be writing to the Cache and to the disk at the same time, thus giving me an extra boost on write speeds.

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