Overclock.net › Forums › Components › Hard Drives & Storage › RAID 0 Slow while copying small files?!
New Posts  All Forums:Forum Nav:

RAID 0 Slow while copying small files?!

post #1 of 6
Thread Starter 
Hi,
So I decided to copy 93GB of assorted word,excel,ppt files from a bad HDD to my D: drive and the transfer rates I got were around 7-9mbps.

I brushed this off thinking the bad HDD is to be blamed.

But when I copied the files to an external HDD, i roughly got the same speed. Why is this? Is it because HDD's become really slow while copying multiple small files? leading to head thrashing?

Or is the external HDD slow?

Thank you
Edited by chip94 - 12/11/12 at 12:37pm
:D
(15 items)
 
  
CPUMotherboardGraphicsRAM
Intel i5 3570K [4.5ghz] Asus P8Z77 V-Pro Asus GTX 760 2X4gb Corsair XMS3 1600mhz 
Hard DriveHard DriveCoolingOS
WD Blue 1TB EZEX X 2 [RAID 0] [WD Black 640GB][2 X WD Blue 1TB EZEX] Corsair H80i Windows 7 64bit 
MonitorPowerCase
Dell Ultrasharp 23" Corsair CX430W v2 Corsair Graphite 600T 
  hide details  
Reply
:D
(15 items)
 
  
CPUMotherboardGraphicsRAM
Intel i5 3570K [4.5ghz] Asus P8Z77 V-Pro Asus GTX 760 2X4gb Corsair XMS3 1600mhz 
Hard DriveHard DriveCoolingOS
WD Blue 1TB EZEX X 2 [RAID 0] [WD Black 640GB][2 X WD Blue 1TB EZEX] Corsair H80i Windows 7 64bit 
MonitorPowerCase
Dell Ultrasharp 23" Corsair CX430W v2 Corsair Graphite 600T 
  hide details  
Reply
post #2 of 6
Seeks take about 10ms on desktop drives. That means the maximum number of file copies you could attain per second is somewhere around 100. (Actually it's higher, but lets keep it simple) - that means at the worst your working 100% health hard drive could perform as slow as 400KB/sec. As files get larger, you get farther from that baseline.

Now, a modern hard drive has about 90-150MB/sec avg read speed, which can be thought of as 90-150KB/ms. Seek to file in 10ms, then read 150KB/ms, or 1.5MB in the next 10ms... if your files are just 1.5MB in size, you'll have a 50/50 split on time wasted seeking, and time spent reading. RAID-0 nearly doubles your sequential read speed, but it does nothing to reduce the seek time, so for files under 1.5MB in size you would get under a 50% performance increase with modern drives.

Files around 64KB or less barely add a milisecond to the time taken to read it over a 4KB file, so for anything small all your time is wasted on seeking. Now take something larger, like a 75MB file - 10ms spent seeking, 500ms spent reading - a much better ratio, so you'll actually get the speeds that you see in benchmarks like HDTune. Large file copies benefit from RAID-0 a lot.

I feel HDTune's RandomAccess benchmark reveals this relationship quite well - only when reads get quite large (~1MB/sec) do you actually get close to a fraction of the drive's sequential performance. Sequential work is what hard drives really love...

hdtuneproahcireadrandom.png

Pay attention to the avg access time - it only goes up ~0.85ms from 4KB to 64KB. Basically nothing. Even 1MB is only 7ms over 4KB. Game devs and software devs should take note of that... it's really cheap reading a few megabytes at a time now, but really expensive seeking to a new file or location.

hdtuneproahcireadbenchm.png
     
CPUMotherboardGraphicsRAM
FX-8350 @ 4.6ghz 1.425v Sabertooth 990FX Zotac GTX 1070 Amp! 32GB (4x8GB) Kingston Fury 1866mhz CL10 1T 1.5v 
Hard DriveHard DriveHard DriveHard Drive
Hitachi 2TB - HDS723020BLA64 Crucial M500 960GB - CT960M500SSD1 WD 4TB Black - WD4001FAEX WD 4TB Black - WD4001FAEX 
Hard DriveHard DriveHard DriveHard Drive
Seagate 2TB - ST2000DM001 WD 640GB Black - WD6401AALS Seagate 6TB - ST6000DM001 Micron M500 - MTFDDAK480MAV 
Optical DriveOptical DriveOptical DriveOptical Drive
Pioneer DVR-115DBK Samsung SH-S243D/BEBE LG GH22NS90 Lite-On EBAU108 External DVD 
CoolingCoolingCoolingOS
Noctua NH-D15 Fractal Design 140mm Fan - FD-FAN-140 Fractal Design 120mm Fan - FD-FAN-120 Windows 7 
OSMonitorMonitorKeyboard
Ubuntu 14.04 LTS Samsung 2343BWX 23" (2048x1152) BenQ GW2765HT 27" IPS LCD Monitor (2560x1440) Genius Keyboard KB-G235 PA 
PowerCaseMouseMouse Pad
Seasonic Platinum 1000w PSU - SS-1000XP Fractal Design Define R5 Steelseries Rival 6500 dcpi Mousepad + Desk 
AudioAudioOtherOther
Onboard Realtek® ALC 892 Cyber Acoustics CA-2992 2.0 Speakers Razer Krait 1600 DPI nGear G-C1601 Card Reader 
OtherOther
Pisen Card Reader Gigabyte M7 Thor 
CPUMotherboardGraphicsRAM
VIA Eden C7 1200mhz Jetway J7F4K1G2ES-LF VIA Onboard 512MB PC2-4200 
Hard DriveOptical DriveCoolingOS
A-Data FlashDrive None Fanless Linux 
MonitorKeyboardPowerCase
Headless None 65w Power Brick Antec ISK300-65 
MouseAudio
None Onboard VIA 
CPUMotherboardGraphicsRAM
Barton XP-M 2400+ FJQ4C Asus A7N8X-E Deluxe 256MB BFG 7800GS OC 2x512MB Samsung PC3200 
Hard DriveOSMonitorKeyboard
Raptor 74GB/Seagate 120GB Windows 2000 Pro 60hz 17" CRT Brandless PS2 Keyboard 
PowerMouse
Antec Neo HE 550w Logitech G5 
  hide details  
Reply
     
CPUMotherboardGraphicsRAM
FX-8350 @ 4.6ghz 1.425v Sabertooth 990FX Zotac GTX 1070 Amp! 32GB (4x8GB) Kingston Fury 1866mhz CL10 1T 1.5v 
Hard DriveHard DriveHard DriveHard Drive
Hitachi 2TB - HDS723020BLA64 Crucial M500 960GB - CT960M500SSD1 WD 4TB Black - WD4001FAEX WD 4TB Black - WD4001FAEX 
Hard DriveHard DriveHard DriveHard Drive
Seagate 2TB - ST2000DM001 WD 640GB Black - WD6401AALS Seagate 6TB - ST6000DM001 Micron M500 - MTFDDAK480MAV 
Optical DriveOptical DriveOptical DriveOptical Drive
Pioneer DVR-115DBK Samsung SH-S243D/BEBE LG GH22NS90 Lite-On EBAU108 External DVD 
CoolingCoolingCoolingOS
Noctua NH-D15 Fractal Design 140mm Fan - FD-FAN-140 Fractal Design 120mm Fan - FD-FAN-120 Windows 7 
OSMonitorMonitorKeyboard
Ubuntu 14.04 LTS Samsung 2343BWX 23" (2048x1152) BenQ GW2765HT 27" IPS LCD Monitor (2560x1440) Genius Keyboard KB-G235 PA 
PowerCaseMouseMouse Pad
Seasonic Platinum 1000w PSU - SS-1000XP Fractal Design Define R5 Steelseries Rival 6500 dcpi Mousepad + Desk 
AudioAudioOtherOther
Onboard Realtek® ALC 892 Cyber Acoustics CA-2992 2.0 Speakers Razer Krait 1600 DPI nGear G-C1601 Card Reader 
OtherOther
Pisen Card Reader Gigabyte M7 Thor 
CPUMotherboardGraphicsRAM
VIA Eden C7 1200mhz Jetway J7F4K1G2ES-LF VIA Onboard 512MB PC2-4200 
Hard DriveOptical DriveCoolingOS
A-Data FlashDrive None Fanless Linux 
MonitorKeyboardPowerCase
Headless None 65w Power Brick Antec ISK300-65 
MouseAudio
None Onboard VIA 
CPUMotherboardGraphicsRAM
Barton XP-M 2400+ FJQ4C Asus A7N8X-E Deluxe 256MB BFG 7800GS OC 2x512MB Samsung PC3200 
Hard DriveOSMonitorKeyboard
Raptor 74GB/Seagate 120GB Windows 2000 Pro 60hz 17" CRT Brandless PS2 Keyboard 
PowerMouse
Antec Neo HE 550w Logitech G5 
  hide details  
Reply
post #3 of 6
Thread Starter 
Thanks for the reply Kramy, but I'm still a bit lost though I think I understood what you've posted . Could you maybe give me an example? redface.gif

EDIT- "it's really cheap reading a few megabytes at a time now, but really expensive seeking to a new file or location."

I think that I missed that last line while I was reading.

But when does the performance really drop? Most of the files I was copying were 15-300kb in size.

And is the performance i'm seeing alright for a pair of Blue 500GB WD's in RAID 0?
Edited by chip94 - 12/11/12 at 12:59pm
:D
(15 items)
 
  
CPUMotherboardGraphicsRAM
Intel i5 3570K [4.5ghz] Asus P8Z77 V-Pro Asus GTX 760 2X4gb Corsair XMS3 1600mhz 
Hard DriveHard DriveCoolingOS
WD Blue 1TB EZEX X 2 [RAID 0] [WD Black 640GB][2 X WD Blue 1TB EZEX] Corsair H80i Windows 7 64bit 
MonitorPowerCase
Dell Ultrasharp 23" Corsair CX430W v2 Corsair Graphite 600T 
  hide details  
Reply
:D
(15 items)
 
  
CPUMotherboardGraphicsRAM
Intel i5 3570K [4.5ghz] Asus P8Z77 V-Pro Asus GTX 760 2X4gb Corsair XMS3 1600mhz 
Hard DriveHard DriveCoolingOS
WD Blue 1TB EZEX X 2 [RAID 0] [WD Black 640GB][2 X WD Blue 1TB EZEX] Corsair H80i Windows 7 64bit 
MonitorPowerCase
Dell Ultrasharp 23" Corsair CX430W v2 Corsair Graphite 600T 
  hide details  
Reply
post #4 of 6
I would have to say that based upon what HE said, the reason why your file transfer on slow files is so slow, is because of the seek time needed to find the files on the hard drive during the copying process.

The smaller the file, the more reads the hard drive has to do, the more time it takes to transfer.
Up & Running
(15 items)
 
  
CPUMotherboardGraphicsRAM
Intel i3-4330 ASRock Fatal1ty Killer Z97 XFX RX 480 16gb G.Skill Ripjaws 1866 
Hard DriveCoolingOSMonitor
1TB Western Digital + WD 400gb + 120gb Intel SSD MCP-655 Vario + XSPC Raystorm + ThermoChill PA1... Windows 10 x64 28" Hanns-G 
KeyboardPowerCaseMouse
Worwolf Mechanical 1000HX Corsair Cooler Master Cosmos S Logitech Optical G400 
Audio
Novation Ultranova 
  hide details  
Reply
Up & Running
(15 items)
 
  
CPUMotherboardGraphicsRAM
Intel i3-4330 ASRock Fatal1ty Killer Z97 XFX RX 480 16gb G.Skill Ripjaws 1866 
Hard DriveCoolingOSMonitor
1TB Western Digital + WD 400gb + 120gb Intel SSD MCP-655 Vario + XSPC Raystorm + ThermoChill PA1... Windows 10 x64 28" Hanns-G 
KeyboardPowerCaseMouse
Worwolf Mechanical 1000HX Corsair Cooler Master Cosmos S Logitech Optical G400 
Audio
Novation Ultranova 
  hide details  
Reply
post #5 of 6
Quote:
Originally Posted by chip94 View Post

EDIT- "it's really cheap reading a few megabytes at a time now, but really expensive seeking to a new file or location."
I'm talking about time there - it's cheap (time wise) reading a few megabytes sequentially, and expensive seeking to another file.
Quote:
Originally Posted by chip94 View Post

I think that I missed that last line while I was reading.

But when does the performance really drop? Most of the files I was copying were 15-300kb in size.

And is the performance i'm seeing alright for a pair of Blue 500GB WD's in RAID 0?

Well, according to that HDTune graph, 64KB files average only 4MB/sec on my Seagate drive. You're getting 7-9MB/sec, so the average filesize must be a tad over 100-120KB. That seems about right for small files.

What I was getting at earlier was, RAID-0 scales your read speed upward by about 95%, but it improves your IOPS (the number of seeks the drive/array can do) by about 0%. For a bunch of 120KB files, that means you drop the seek time by nothing (still 10ms) and drop the read time from about 1.6ms to 0.8ms. Basically, for this kind of file copying, your RAID-0 array improves the per-file copy time from ~11.6ms to ~10.8ms. (Not much - but you get a much larger boost on larger files that can be read longer before the next seek to the next file.)
     
CPUMotherboardGraphicsRAM
FX-8350 @ 4.6ghz 1.425v Sabertooth 990FX Zotac GTX 1070 Amp! 32GB (4x8GB) Kingston Fury 1866mhz CL10 1T 1.5v 
Hard DriveHard DriveHard DriveHard Drive
Hitachi 2TB - HDS723020BLA64 Crucial M500 960GB - CT960M500SSD1 WD 4TB Black - WD4001FAEX WD 4TB Black - WD4001FAEX 
Hard DriveHard DriveHard DriveHard Drive
Seagate 2TB - ST2000DM001 WD 640GB Black - WD6401AALS Seagate 6TB - ST6000DM001 Micron M500 - MTFDDAK480MAV 
Optical DriveOptical DriveOptical DriveOptical Drive
Pioneer DVR-115DBK Samsung SH-S243D/BEBE LG GH22NS90 Lite-On EBAU108 External DVD 
CoolingCoolingCoolingOS
Noctua NH-D15 Fractal Design 140mm Fan - FD-FAN-140 Fractal Design 120mm Fan - FD-FAN-120 Windows 7 
OSMonitorMonitorKeyboard
Ubuntu 14.04 LTS Samsung 2343BWX 23" (2048x1152) BenQ GW2765HT 27" IPS LCD Monitor (2560x1440) Genius Keyboard KB-G235 PA 
PowerCaseMouseMouse Pad
Seasonic Platinum 1000w PSU - SS-1000XP Fractal Design Define R5 Steelseries Rival 6500 dcpi Mousepad + Desk 
AudioAudioOtherOther
Onboard Realtek® ALC 892 Cyber Acoustics CA-2992 2.0 Speakers Razer Krait 1600 DPI nGear G-C1601 Card Reader 
OtherOther
Pisen Card Reader Gigabyte M7 Thor 
CPUMotherboardGraphicsRAM
VIA Eden C7 1200mhz Jetway J7F4K1G2ES-LF VIA Onboard 512MB PC2-4200 
Hard DriveOptical DriveCoolingOS
A-Data FlashDrive None Fanless Linux 
MonitorKeyboardPowerCase
Headless None 65w Power Brick Antec ISK300-65 
MouseAudio
None Onboard VIA 
CPUMotherboardGraphicsRAM
Barton XP-M 2400+ FJQ4C Asus A7N8X-E Deluxe 256MB BFG 7800GS OC 2x512MB Samsung PC3200 
Hard DriveOSMonitorKeyboard
Raptor 74GB/Seagate 120GB Windows 2000 Pro 60hz 17" CRT Brandless PS2 Keyboard 
PowerMouse
Antec Neo HE 550w Logitech G5 
  hide details  
Reply
     
CPUMotherboardGraphicsRAM
FX-8350 @ 4.6ghz 1.425v Sabertooth 990FX Zotac GTX 1070 Amp! 32GB (4x8GB) Kingston Fury 1866mhz CL10 1T 1.5v 
Hard DriveHard DriveHard DriveHard Drive
Hitachi 2TB - HDS723020BLA64 Crucial M500 960GB - CT960M500SSD1 WD 4TB Black - WD4001FAEX WD 4TB Black - WD4001FAEX 
Hard DriveHard DriveHard DriveHard Drive
Seagate 2TB - ST2000DM001 WD 640GB Black - WD6401AALS Seagate 6TB - ST6000DM001 Micron M500 - MTFDDAK480MAV 
Optical DriveOptical DriveOptical DriveOptical Drive
Pioneer DVR-115DBK Samsung SH-S243D/BEBE LG GH22NS90 Lite-On EBAU108 External DVD 
CoolingCoolingCoolingOS
Noctua NH-D15 Fractal Design 140mm Fan - FD-FAN-140 Fractal Design 120mm Fan - FD-FAN-120 Windows 7 
OSMonitorMonitorKeyboard
Ubuntu 14.04 LTS Samsung 2343BWX 23" (2048x1152) BenQ GW2765HT 27" IPS LCD Monitor (2560x1440) Genius Keyboard KB-G235 PA 
PowerCaseMouseMouse Pad
Seasonic Platinum 1000w PSU - SS-1000XP Fractal Design Define R5 Steelseries Rival 6500 dcpi Mousepad + Desk 
AudioAudioOtherOther
Onboard Realtek® ALC 892 Cyber Acoustics CA-2992 2.0 Speakers Razer Krait 1600 DPI nGear G-C1601 Card Reader 
OtherOther
Pisen Card Reader Gigabyte M7 Thor 
CPUMotherboardGraphicsRAM
VIA Eden C7 1200mhz Jetway J7F4K1G2ES-LF VIA Onboard 512MB PC2-4200 
Hard DriveOptical DriveCoolingOS
A-Data FlashDrive None Fanless Linux 
MonitorKeyboardPowerCase
Headless None 65w Power Brick Antec ISK300-65 
MouseAudio
None Onboard VIA 
CPUMotherboardGraphicsRAM
Barton XP-M 2400+ FJQ4C Asus A7N8X-E Deluxe 256MB BFG 7800GS OC 2x512MB Samsung PC3200 
Hard DriveOSMonitorKeyboard
Raptor 74GB/Seagate 120GB Windows 2000 Pro 60hz 17" CRT Brandless PS2 Keyboard 
PowerMouse
Antec Neo HE 550w Logitech G5 
  hide details  
Reply
post #6 of 6
Thread Starter 
Now I totally get it. I was worried that my drives weren't performing well.

Once again, thanks a lot Kramy ! thumb.gif

rep+
:D
(15 items)
 
  
CPUMotherboardGraphicsRAM
Intel i5 3570K [4.5ghz] Asus P8Z77 V-Pro Asus GTX 760 2X4gb Corsair XMS3 1600mhz 
Hard DriveHard DriveCoolingOS
WD Blue 1TB EZEX X 2 [RAID 0] [WD Black 640GB][2 X WD Blue 1TB EZEX] Corsair H80i Windows 7 64bit 
MonitorPowerCase
Dell Ultrasharp 23" Corsair CX430W v2 Corsair Graphite 600T 
  hide details  
Reply
:D
(15 items)
 
  
CPUMotherboardGraphicsRAM
Intel i5 3570K [4.5ghz] Asus P8Z77 V-Pro Asus GTX 760 2X4gb Corsair XMS3 1600mhz 
Hard DriveHard DriveCoolingOS
WD Blue 1TB EZEX X 2 [RAID 0] [WD Black 640GB][2 X WD Blue 1TB EZEX] Corsair H80i Windows 7 64bit 
MonitorPowerCase
Dell Ultrasharp 23" Corsair CX430W v2 Corsair Graphite 600T 
  hide details  
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Hard Drives & Storage
Overclock.net › Forums › Components › Hard Drives & Storage › RAID 0 Slow while copying small files?!