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Sent from my BlackBerry Handheld.


----- Original Message -----
From: linux-iscsi-users-request
Sent: 09/17/2007 01:05 PM
To: linux-iscsi-users@xxxxxxxxxxxxxxxxxxxxx
Subject: linux-iscsi-users Digest, Vol 14, Issue 1



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Today's Topics:

   1. Good write bad read times (joshi)
   2. Re: Good write bad read times (iscsi)
   3. Re: Good write bad read times (Hiren Joshi)
   4. Re: Good write bad read times (iscsi)
   5. Re: Good write bad read times (Hiren Joshi)


----------------------------------------------------------------------

Message: 1
Date: Mon, 17 Sep 2007 06:35:03 -0700 (PDT)
From: joshi <josh@xxxxxxxxxxxxx>
Subject:  Good write bad read times
To: linux-iscsi-users@xxxxxxxxxxxxxxxxxxxxx
Message-ID: <12735484.post@xxxxxxxxxxxxxxx>
Content-Type: text/plain; charset=us-ascii


Sorry if I've already posted this.
 
This is weird, I have Dell (EMC) Ax150i running centos4.4
2.6.9-42.ELsmp
iscsi-initiator-utils-4.0.3.0-5
 
My write speed (dd about 10GB to the disk) is 250MB/s This is good.
My read speed (dd 10GB from the disk to /dev/null) is about 3MB/s Bad =(
 
I'm using the default config for iscsid and am at my wits end, can anyone on
this list point me in the right direction?
 
Thanks,
Josh.
-- 
View this message in context: http://www.nabble.com/Good-write-bad-read-times-tf4466582.html#a12735484
Sent from the linux-iscsi-users mailing list archive at Nabble.com.




------------------------------

Message: 2
Date: Mon, 17 Sep 2007 13:46:53 -0300
From: iscsi <iscsi@xxxxxxxxxxxxxx>
Subject: Re:  Good write bad read times
To: joshi <josh@xxxxxxxxxxxxx>
Cc: linux-iscsi-users@xxxxxxxxxxxxxxxxxxxxx
Message-ID: <46EEAF7D.20009@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset=us-ascii; format=flowed


how did you measure those values ? e.g 10GB to the disk !!!!
have you used any software for this benchmark.



joshi wrote:
> Sorry if I've already posted this.
>  
> This is weird, I have Dell (EMC) Ax150i running centos4.4
> 2.6.9-42.ELsmp
> iscsi-initiator-utils-4.0.3.0-5
>  
> My write speed (dd about 10GB to the disk) is 250MB/s This is good.
> My read speed (dd 10GB from the disk to /dev/null) is about 3MB/s Bad =(
>  
> I'm using the default config for iscsid and am at my wits end, can anyone on
> this list point me in the right direction?
>  
> Thanks,
> Josh.
>   




------------------------------

Message: 3
Date: Mon, 17 Sep 2007 17:57:52 +0100
From: "Hiren Joshi" <josh@xxxxxxxxxxxxx>
Subject: Re:  Good write bad read times
To: "iscsi" <iscsi@xxxxxxxxxxxxxx>
Cc: linux-iscsi-users@xxxxxxxxxxxxxxxxxxxxx
Message-ID:
	<37238624DE95654997C360CA6CD36F8403B5BB77@xxxxxxxxxxxxxxxxxxxxxx>
Content-Type: text/plain;	charset="us-ascii"

I did a basic dd if=/dev/zero to the disk then dd to /dev/null from the
disk, timing.

Also:
hdparm -tT /dev/sdc
/dev/sdc:
 Timing cached reads:   4764 MB in  2.00 seconds = 2383.55 MB/sec
 Timing buffered disk reads:   10 MB in  3.46 seconds =   2.89 MB/sec 

Also tried dd if=/dev/sdc of=/dev/null bs=4096 count=512.... Tried
bonnie++, all tests point to the same thing, that is, I can write
150MB/s but can only read 3MB/s.


-----Original Message-----
From: linux-iscsi-users-bounces@xxxxxxxxxxxxxxxxxxxxx
[mailto:linux-iscsi-users-bounces@xxxxxxxxxxxxxxxxxxxxx] On Behalf Of
iscsi
Sent: 17 September 2007 17:47
To: Hiren Joshi
Cc: linux-iscsi-users@xxxxxxxxxxxxxxxxxxxxx
Subject: Re:  Good write bad read times


how did you measure those values ? e.g 10GB to the disk !!!!
have you used any software for this benchmark.



joshi wrote:
> Sorry if I've already posted this.
>  
> This is weird, I have Dell (EMC) Ax150i running centos4.4 
> 2.6.9-42.ELsmp
> iscsi-initiator-utils-4.0.3.0-5
>  
> My write speed (dd about 10GB to the disk) is 250MB/s This is good.
> My read speed (dd 10GB from the disk to /dev/null) is about 3MB/s Bad 
> =(
>  
> I'm using the default config for iscsid and am at my wits end, can 
> anyone on this list point me in the right direction?
>  
> Thanks,
> Josh.
>   


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------------------------------

Message: 4
Date: Mon, 17 Sep 2007 14:01:08 -0300
From: iscsi <iscsi@xxxxxxxxxxxxxx>
Subject: Re:  Good write bad read times
To: Hiren Joshi <josh@xxxxxxxxxxxxx>
Cc: linux-iscsi-users@xxxxxxxxxxxxxxxxxxxxx
Message-ID: <46EEB2D4.2010405@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset=us-ascii; format=flowed

are you using RAID 5.
I believe RAID 5 Read is less than write.
Striping hard drives will improve read and write access.
however still speed difference shouldn't be this much.


Hiren Joshi wrote:
> I did a basic dd if=/dev/zero to the disk then dd to /dev/null from the
> disk, timing.
>
> Also:
> hdparm -tT /dev/sdc
> /dev/sdc:
>  Timing cached reads:   4764 MB in  2.00 seconds = 2383.55 MB/sec
>  Timing buffered disk reads:   10 MB in  3.46 seconds =   2.89 MB/sec 
>
> Also tried dd if=/dev/sdc of=/dev/null bs=4096 count=512.... Tried
> bonnie++, all tests point to the same thing, that is, I can write
> 150MB/s but can only read 3MB/s.
>
>
> -----Original Message-----
> From: linux-iscsi-users-bounces@xxxxxxxxxxxxxxxxxxxxx
> [mailto:linux-iscsi-users-bounces@xxxxxxxxxxxxxxxxxxxxx] On Behalf Of
> iscsi
> Sent: 17 September 2007 17:47
> To: Hiren Joshi
> Cc: linux-iscsi-users@xxxxxxxxxxxxxxxxxxxxx
> Subject: Re:  Good write bad read times
>
>
> how did you measure those values ? e.g 10GB to the disk !!!!
> have you used any software for this benchmark.
>
>
>
> joshi wrote:
>   
>> Sorry if I've already posted this.
>>  
>> This is weird, I have Dell (EMC) Ax150i running centos4.4 
>> 2.6.9-42.ELsmp
>> iscsi-initiator-utils-4.0.3.0-5
>>  
>> My write speed (dd about 10GB to the disk) is 250MB/s This is good.
>> My read speed (dd 10GB from the disk to /dev/null) is about 3MB/s Bad 
>> =(
>>  
>> I'm using the default config for iscsid and am at my wits end, can 
>> anyone on this list point me in the right direction?
>>  
>> Thanks,
>> Josh.
>>   
>>     
>
>
> ------------------------------------------------------------------------
> -
> This SF.net email is sponsored by: Microsoft Defy all challenges.
> Microsoft(R) Visual Studio 2005.
> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
> _______________________________________________
> linux-iscsi-users mailing list
> linux-iscsi-users@xxxxxxxxxxxxxxxxxxxxx
> https://lists.sourceforge.net/lists/listinfo/linux-iscsi-users
>
>   




------------------------------

Message: 5
Date: Mon, 17 Sep 2007 18:09:49 +0100
From: "Hiren Joshi" <josh@xxxxxxxxxxxxx>
Subject: Re:  Good write bad read times
To: "iscsi" <iscsi@xxxxxxxxxxxxxx>
Cc: linux-iscsi-users@xxxxxxxxxxxxxxxxxxxxx
Message-ID:
	<37238624DE95654997C360CA6CD36F8403B5BB79@xxxxxxxxxxxxxxxxxxxxxx>
Content-Type: text/plain;	charset="us-ascii"

Indeed, 3MB/s tells me something is really wrong some ware. I tried it
with a RAID 1 as well, again read is ~=3MB/s.

I have used 2 servers and both nics on the AX150i, it gives me the same
results. 

-----Original Message-----
From: iscsi [mailto:iscsi@xxxxxxxxxxxxxx] 
Sent: 17 September 2007 18:01
To: Hiren Joshi
Cc: linux-iscsi-users@xxxxxxxxxxxxxxxxxxxxx
Subject: Re:  Good write bad read times

are you using RAID 5.
I believe RAID 5 Read is less than write.
Striping hard drives will improve read and write access.
however still speed difference shouldn't be this much.


Hiren Joshi wrote:
> I did a basic dd if=/dev/zero to the disk then dd to /dev/null from 
> the disk, timing.
>
> Also:
> hdparm -tT /dev/sdc
> /dev/sdc:
>  Timing cached reads:   4764 MB in  2.00 seconds = 2383.55 MB/sec
>  Timing buffered disk reads:   10 MB in  3.46 seconds =   2.89 MB/sec 
>
> Also tried dd if=/dev/sdc of=/dev/null bs=4096 count=512.... Tried
> bonnie++, all tests point to the same thing, that is, I can write
> 150MB/s but can only read 3MB/s.
>
>
> -----Original Message-----
> From: linux-iscsi-users-bounces@xxxxxxxxxxxxxxxxxxxxx
> [mailto:linux-iscsi-users-bounces@xxxxxxxxxxxxxxxxxxxxx] On Behalf Of 
> iscsi
> Sent: 17 September 2007 17:47
> To: Hiren Joshi
> Cc: linux-iscsi-users@xxxxxxxxxxxxxxxxxxxxx
> Subject: Re:  Good write bad read times
>
>
> how did you measure those values ? e.g 10GB to the disk !!!!
> have you used any software for this benchmark.
>
>
>
> joshi wrote:
>   
>> Sorry if I've already posted this.
>>  
>> This is weird, I have Dell (EMC) Ax150i running centos4.4 
>> 2.6.9-42.ELsmp
>> iscsi-initiator-utils-4.0.3.0-5
>>  
>> My write speed (dd about 10GB to the disk) is 250MB/s This is good.
>> My read speed (dd 10GB from the disk to /dev/null) is about 3MB/s Bad

>> =(
>>  
>> I'm using the default config for iscsid and am at my wits end, can 
>> anyone on this list point me in the right direction?
>>  
>> Thanks,
>> Josh.
>>   
>>     
>
>
> ----------------------------------------------------------------------
> --
> -
> This SF.net email is sponsored by: Microsoft Defy all challenges.
> Microsoft(R) Visual Studio 2005.
> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
> _______________________________________________
> linux-iscsi-users mailing list
> linux-iscsi-users@xxxxxxxxxxxxxxxxxxxxx
> https://lists.sourceforge.net/lists/listinfo/linux-iscsi-users
>
>   




------------------------------

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End of linux-iscsi-users Digest, Vol 14, Issue 1
************************************************

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