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-   -   Rediculously slow write times with Supermicro Board, SATA drives (https://www.linuxquestions.org/questions/linux-hardware-18/rediculously-slow-write-times-with-supermicro-board-sata-drives-676350/)

abefroman 10-14-2008 04:41 PM
Rediculously slow write times with Supermicro Board, SATA drives
 
I am getting rediculously slow write times on my Supermicro Board with SATA drives.

Any idea what could be causing this? It writes at about 14mbps.

trickykid 10-14-2008 05:03 PM
Probably need more info. Logs, what exactly it is you're writing, any tests or benchmarks you've tried, etc? How it's setup, RAID, H/W RAID, etc?

abefroman 10-14-2008 07:04 PM
Quote:
Originally Posted by trickykid (Post 3310149)
Probably need more info. Logs, what exactly it is you're writing, any tests or benchmarks you've tried, etc? How it's setup, RAID, H/W RAID, etc?
No raid or anything, the drives are connected right to the board.

Here is the test I ran:
# time dd if=/dev/zero of=file bs=1024 count=512288
512288+0 records in
512288+0 records out
524582912 bytes (525 MB) copied, 35.2333 seconds, 14.9 MB/s

real 0m35.275s
user 0m0.844s
sys 0m10.461s

forum1793 10-14-2008 07:26 PM
How is SATA set up in bios?
What is your kernel?
What are DMA results?

abefroman 10-22-2008 11:11 PM
Quote:
Originally Posted by forum1793 (Post 3310269)
What are DMA results?
How do I get the DMA output?

jiml8 10-23-2008 12:22 AM
What else is running on your system that might contend with this test for I/O bandwidth? Memory limitations leading to swapping perhaps?

AuroraCA 10-23-2008 12:33 AM
You are reading from /dev/zero and writing to a file called "file". Where is "file" located? Is it on the same disk that you are reading from? This presumes that you are executing the dd command while in on /dev/zero

Please list the specific device names so that it is easier to understand what you are doing. Too many people write a description of what they are trying to do instead of actually what they are doing and without precise information it is impossible to give a specific if not precise answer.

H_TeXMeX_H 10-23-2008 03:10 AM
First try booting with kernel option "hda=noprobe", and see if it works better. If not, try putting the drive in AHCI mode in the BIOS, make sure you have ahci enabled in the kernel.

jiml8 10-23-2008 10:13 AM
Quote:
Originally Posted by AuroraCA (Post 3319394)
You are reading from /dev/zero and writing to a file called "file". Where is "file" located? Is it on the same disk that you are reading from? This presumes that you are executing the dd command while in on /dev/zero

Please list the specific device names so that it is easier to understand what you are doing. Too many people write a description of what they are trying to do instead of actually what they are doing and without precise information it is impossible to give a specific if not precise answer.
/dev/zero is a virtual file maintained by the kernel to generate zeros upon demand. It does not exist on any drive anyplace. The test is valid, as far as it goes, to measure drive write speed.

When I ran the identical command in a bash window I opened, pointed at my home directory, on my heavily loaded and busy workstation, I got 47 mB/sec. The target drive is a 10K RPM SCSI drive.

AuroraCA 10-23-2008 10:18 AM
Quote:
Originally Posted by jiml8 (Post 3319752)
/dev/zero is a virtual file maintained by the kernel to generate zeros upon demand. It does not exist on any drive anyplace. The test is valid, as far as it goes, to measure drive write speed.

When I ran the identical command in a bash window I opened, pointed at my home directory, on my heavily loaded and busy workstation, I got 47 mB/sec. The target drive is a 10K RPM SCSI drive.
Thank you. I did not know that.

I ran the same test on an old server with IDE drives and it took 13.2785 seconds with 39.5 MB/s transfer.


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