NAS perk - performance of SATA disks vs. USB3 connected disks

Turris Omnia
1

Turris team,

have you measured the performance of disks connected over SATA (NAS perk) vs. the same disks connected over USB3? I’m interested mainly in the performance difference over LAN.

As the NAS perk is no longer available for purchase - what is the SATA controller used in it? I’m considering buying it separately but I haven’t found any details.

Thanks.
Radek

2

The chipset is a Asmedia one. There is already a thread about this: https://discourse.labs.nic.cz/t/the-minipcie-sata-controller-specification/534/3

Perfomance for USB3 with UASP capable drive adapter chipset will probably make no big difference. You may hit the drive maximum throughput for the inner cylinders, get limited by the CPU because of protocol overhead or even by the network latency. There are far more factors.

For media (audio, video, images) this will make no practical difference…

3

Can anybody confirm if Omnia will support the UASP capable disks when the disc enclosures will support it? I tried to look at Armada’s specs however couldn’t find any reference. The latest TurrisOS is based on OpenWRT 15.05 which is using kernel 3.18 so I “assume” the UASP support should be available in kernel however I read about some complication with certain chipsets and therefore that the set of supported HW is relatively limited.

If the support is available then it would be probably an option instead of NAS - I could use the internal mSATA disk for more intensive disk operations and use the USB3-UASP for files served over network (home drives, backups, media files)

4

UASP seems to be independent of the host because even my old intel USB2 controller works with uas and not usb-storage. Only exceptions seem to be the ASM1042, a VIA one and some unknown controller because of bugs with streams in the controller.

It is more the way around that not all device (enclosure) chipsets work because of bugs in the chipset firmware.

5

Actually Omnia uses 4.4 kernel. One of the things where it differs from released OpenWRT. No idea about UASP, don’t have one and never even met one.

6

Could anybody with the NAS perk pls test the HDD performance when the disk is connected over SATA vs. USB3?

I’m considering:

  1. Using USB3 connected disks only
  2. Using mSata SSD disk + USB3 connected disks
  3. Buying SATA controller (similar to one in NAS perk) and have the disk placed next to the Omnia router in my rack

Options 1 or 2 would be easier but I’d like to understand the performance difference vs. SATA disks over LAN.
Also do you know if the 2 USB3 ports are independent or not? Meaning if I connect two USB3 disks and would copy files from one to the other - would it impact the copy speed?

7

I could check as soon as the router arrives. I have got two 4 TB WD Blue (taken out of WD Elements external drives).

However, I would need some help as I am not familiar at all with OpenWRT. Or would Windows-screenshots suffice for your comparison?

8

That should be fine. I’m interested in the speed difference when copying to/from a computer to disk connected to Omnia (1. disk connected over USB3, 2. disk connected over SATA). To eliminate the instability of wireless it would be better to have the computer connected over LAN port.

9

OK. I’ve got a wired GBit-Ethernet network set up and I will copy data from my PC. The drive I will be copying from will be a 500 GB Samsung Evo 850, the network chip on my motherboard (Zotac H87 ITX) should be a Realtek RTL8111B.

I guess I will test with a big file (> 4 GB, i.e. ISO), several smaller files (music FLAC, usually around 40-50 MB) and very small files. I’m not sure where I will get small files from.

10

ad 3.

hdparm -itT /dev/sda

/dev/sda:

Model=WDC WD20EFRX-68EUZN0, FwRev=82.00A82, SerialNo=WD-WCC4M6ARAFPL
Config={ HardSect NotMFM HdSw>15uSec SpinMotCtl Fixed DTR>5Mbs FmtGapReq }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=0
BuffType=unknown, BuffSize=unknown, MaxMultSect=16, MultSect=off
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=3907029168
IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6
AdvancedPM=no WriteCache=enabled
Drive conforms to: Unspecified: ATA/ATAPI-1,2,3,4,5,6,7

  • signifies the current active mode

Timing cached reads: 1336 MB in 2.00 seconds = 668.05 MB/sec
Timing buffered disk reads: 454 MB in 3.00 seconds = 151.18 MB/sec

Copying with rsyncd over Gb ethernet to pc is about 50 MB/s

11

Thanks @fickk for the performance numbers for SATA connected disks.

All USB disks I have at home are just older USB 2.0. Could anybody with USB 3.0 connected disk measure the transfer speed for comparison?

12

Hi @radekpribyl

I connected SSD disk (ADATA SU800 256 GB) by USB 3.0 and measure transfer speed.

Timing cached reads: 1320 MB in 2.00 seconds = 660.23 MB/sec
Timing buffered disk reads: 578 MB in 3.01 seconds = 192.05 MB/sec

13

Information about buffered and cached read speeds are practically useless, because the network speed is slower. Theoretical maximum speed for gigabit ethernet is around 125 MB/s. If you are testing read speeds, please test it over the ethernet (copy with ftp, samba, rsync, etc). Thx.

14

Hi @radekpribyl,

I tested following case: “read one 1GB file from USB3.0 vs. mSATA” to computer connected via ethernet:

(a) Samsung SSD T3 1TB (NTFS formatted) - 112 MB/s
(b) Samsung mSATA 850EVO 1TB (ext4 formatted) - 113 MB/s

As far as I know, the internal memory component of the T3 USB SSD is a 850EVO as well.
So - no speed difference.