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RAID 1 speed slow: read 140 MB/s, write 170 MB/s


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Hi,

 

I just upgraded my whole network to 10 GbE, but I am getting strange results while copying a file from and to my Diskstation.

The read speed is slow compared to my write speed.

 

Diskstation: RAID 1, 2x WD Red (same for other RAID 1 configurations in this Diskstation)

PC: SSD

 

Write speed: ~170 MB/s
Read speed: ~140 MB/s

 

Shouldn't it be the opposite?! Also the read speed should be faster than 170 MB/s.

 

Using different the SATA ports? But I am already using my 6 onboard SATA ports and 2 from an Marvell 88SE9215.

 

Diskstation runs on a Gigabyte Z370P D3 with an Intel Core i5-8400 and 8 GB RAM.

No VM, no apps and so on.

 

Thanks!

Edited by Xairoo
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2 hours ago, Xairoo said:

sing different the SATA ports? But I am already using my 6 onboard SATA ports and 2 from an Marvell 88SE9215.

the onboard-chipset sata should be ok, the 88se9215 is just one pcie 2.0 lane so max. 500MB/s (at best) for whatever is connected to this controller

 

raid1 is just reading from a single disk so you can't expect more the 200-220 MB/s at best

you can use hdparm to estimate the disk and disk interface speed

https://www.shellhacks.com/disk-speed-test-read-write-hdd-ssd-perfomance-linux/ (or use forum search)

for network speed (leaving out disks of the equation) you can user synocli-monitor package, that comes with iperf3 (windows version also available for the client if needed https://iperf.fr/iperf-download.php)

for more details use the forum search, its not a unusual problem trying to narrow down performance problems

 

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4 hours ago, IG-88 said:

raid1 is just reading from a single disk so you can't expect more the 200-220 MB/s at best

 

All right, got it, thanks! Was confused because I had 370 MB/s write speed with a 1 GB file, but that changed after copying a 20 GB file ;)

 

I should change to SHR 1 or 2 I guess. But backing up such amount of data requires a new backup from the backup strategy. Currently rotation weekly multiple single disks for every RAID 1, that works great (simple rsync from each RAID 1 to the target disk), but that's not a good solution for a big SHR volume.

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1 minute ago, Xairoo said:

ll right, got it, thanks! Was confused because I had 370 MB/s write speed with a 1 GB file, but that changed after copying a 20 GB file

when writing to the nas the ram will be used for caching so 1GB will fir into cache and deliver a higher write rate, you should see the dip when writing bigger files that exeed the ram of the nas, win10 hast a nice graphical view when extending the view so often you can see that if you know your hardware an look for it

separate disk and network performance and keep in mind that even when using a ssd/nvme cache its no good when reading from nas as in a one user environment your read (ssd) cache will not contain the data in question and need to be read from disk and with just raid1 of two disk will not be that mutch

so depending on how you plan to use your nas it can be more beneficial to have a extra ssd volume instead of ssd cache and in cases like video editing it might be better to have the ssd's on the system you are working with

 

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59 minutes ago, Xairoo said:

I should change to SHR 1 or 2 I guess.

 

SHR with 2 drives is the same as RAID 1.  And WD Reds are quite slow for what it's worth.  I don't think your speeds are completely out of line.

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What a pain, still slow with RAID 10 or even RAID 0.

 

RAID 10 with 8x4TB WD Red drives:

Read 170 MB/s

Write 160 MB/s

 

With RAID 0, 8x4TB:

Read 120 MB/s

Write 170 MB/s

 

Iperf3 9,9 Gbit/s.

 

I have jumbo frames enabled.

 

Local source and target drive is a NVMe. But also CrystalDiskMark gives me that bad results.

 

Can it be the Core i3-4130? Hmmm, I have no idea.

Edited by Xairoo
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