Gigabit ethernet speed disappointment

Discussion in 'iMac' started by philipz, Nov 18, 2007.

  1. philipz macrumors newbie

    Joined:
    Apr 28, 2006
    #1
    All,

    I did some tests this weekend with my gigabit ethernet driven home network.
    1 iMac 2.4 with 4GB RAM, 1 Linksys gigabit switch and 1 Lacie Bigdisk 1TB NAS, also gigabit.

    I don't get more than 160 Mbit throughput to my NAS, with jumbo frames enabled on all devices. Ports are all set to 1000/Full (so no auto-sensing).
    Protocol (SMB/FTP/AFP) gives only minor differences. When turning jumbo frames off, I lose about 30% of the throughput.
    When I test the throughput only (so no disks involved) with iPerf (between my iMac and a PC on the other side instead of the NAS) I get a throughput of 700 to 800 Mbits. So my cable (cat5e or cat6, don't recall) is definitely capable of high throughput. So between my Mac and my NAS I barely get 25% of the iPerf throughput.

    Any ideas?

    Tx
     
  2. negatv1 macrumors 6502

    Joined:
    Aug 12, 2005
    Location:
    MI
    #2
    Likely your NAS is the cause of your performance woes.

    I can say from my own experiences with some homebrew NAS boxes I've built, I've found that Samba over gigabit just doesn't perform as well as say, a Windows share.

    The results from iPerf are great, but basically only tells you that your gigabit network hardware is working as it should and doesn't tell you much in regards to actually copying files over SMB/AFS, etc. Would be interested in seeing the comparison of copying files to/from your NAS vs. the same files to a Windows share to see how they compare.
     
  3. DoFoT9 macrumors P6

    DoFoT9

    Joined:
    Jun 11, 2007
    Location:
    Singapore
    #3
    remember that your NAS will only read at like 60-200mbps or something....depending on the configuration and whatnot of hard drives
     
  4. Big-TDI-Guy macrumors 68030

    Big-TDI-Guy

    Joined:
    Jan 11, 2007
    #4
    I have yet to see a NAS device that can even use a good chunk of Gigabit ethernet - which is why I don't have one.

    Many consumer NAS solutions are notoriously slow.
     
  5. edesignuk Moderator emeritus

    edesignuk

    Joined:
    Mar 25, 2002
    Location:
    London, England
    #5
    I'd also go with the Lacie being the problem here. Just a restriction of the drives and configuration. Basically I think your network is more capable than the drive is. Not a lot you can do...unless you want to pay out a lot of cash for a well spec'd RAID array with SAS or SCSI drives.
     
  6. Big-TDI-Guy macrumors 68030

    Big-TDI-Guy

    Joined:
    Jan 11, 2007
    #6
    Basic home NAS drives don't exactly have the pick of the liter hard drive and hard drive controllers in them.

    Usually - it's thought you don't need the speed with a ethernet interface - so component selection / optimization seems to be a bit of an afterthought.

    This should reverse with more of the Gigabit and Dual Gigabit ethernets popping up everywhere.

    Once I can find a decent gigabit router for a low price - hopefully then NAS will have sped up enough to make a worthwhile purchase.

    I love my WD Netcenter in the basement - safe from "threats" up here. Feel a little better having some of my backup elsewhere.... Just in case someone likes my PC enough to make it their own...
     
  7. philipz thread starter macrumors newbie

    Joined:
    Apr 28, 2006
    #7
    Today I did a quick test with my pc running Filezilla server, putting a file on it from my Mac. Maximum speed was 120 Mbits, with very inconsistent throughput (from 50 to 120 Mbit). Not sure if Filezilla or the protocol is the bottleneck. Have to admit that it is not the newest PC though.
    So this test didn't reveal the bottleneck either...

    What I'm wondering; why are vendors selling a gigabit NAS if that system can't handle that speed? It's the last thing that came up to my mind when trying to find the bottleneck :(
     
  8. edesignuk Moderator emeritus

    edesignuk

    Joined:
    Mar 25, 2002
    Location:
    London, England
    #8
    ^ Because slapping "Gigabit" on packaging and using a gigabit port doesn't cost them squat, but makes it look better than 10/100 based systems ;)
     
  9. wakerider017 macrumors 68000

    wakerider017

    Joined:
    Sep 20, 2006
    Location:
    US of A
    #9
    I have a great connection speed between my macs.

    (Using a netgear gigabit switch, behind a linksys router.) I have a pretty nice network setup :)
     
  10. philipz thread starter macrumors newbie

    Joined:
    Apr 28, 2006
    #10
    Can t-you define 'great connection speed'? Which speed exactly?
    All gigabit devices?
     
  11. jf8 macrumors regular

    Joined:
    Aug 8, 2007
    #11
    I've got an iMac (mid-2007) 20" 2.4GHz with 4GB of RAM, and the WD 320GB 7200rpm hard drive. Using gigabit ethernet to a budget Dell web-managed switch, I've transferred over 55mbytes/sec both ways to my "NAS" -- which is probably about the max speed of the drive in the iMac.

    The "NAS" is a Linux box. Currently, it's a Core 2 Duo E6550 2.33GHz, 8GB RAM, and the storage is a 5-drive RAID5 running over a single port multiplier channel. Maximum throughput is 120 mbytes/sec, and this is a hardware limitation in the controller card I'm using. I used samba 3.0.24 and mapped the drive through the Finder.

    Before Leopard, I only got 45mbytes/sec. However, I was also using a slower Linux server (Pentium M 2.13GHz) with a different NIC and an older Linux kernel (precompiled 2.6.22 32-bit vs 2.6.23 64-bit). Any one of those variables could have contributed to the slower speeds experienced while using Tiger.

    The CPU usage on the file server is minimal, and any sufficiently fast CPU (<1-1.5GHz I'd imagine) should be able to come close to saturating a Gigabit Ethernet connection with minimal tweaking, providing the bandwidth is there between the CPU and disks/network.
     

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