Re: Abort Task ?

["BERTRAND Joël" <joel.bertrand@systella.fr>]

Ross S. W. Walker wrote:
> BERTRAND Joël wrote:
>> BERTRAND Joël wrote:
>>>     I can format serveral times (mkfs.ext3) a 1.5 TB volume 
>> over iSCSI 
>>> without any trouble. I can read and write on this virtual 
>> disk without 
>>> any trouble.
>>>
>>>     Now, I have configured ietd with :
>>>
>>> Lun 0 Sectors=1464725758,Type=nullio
>>>
>>> and I run on initiator side :
>>>
>>> Root gershwin:[/dev] > dd if=/dev/zero of=/dev/sdj bs=8192
>>> 479482+0 records in
>>> 479482+0 records out
>>> 3927916544 bytes (3.9 GB) copied, 153.222 seconds, 25.6 MB/s
>>>
>>> Root gershwin:[/dev] > dd if=/dev/zero of=/dev/sdj bs=8192
>>>
>>>     I'm waitinfor a crash. No one when I write these lines. 
>>    I suspect 
>>> an interaction between raid and iscsi.
>> 	I simultanely run :
>>
>> Root gershwin:[/dev] > dd if=/dev/zero of=/dev/sdj bs=8192
>> 8397210+0 records in
>> 8397210+0 records out
>> 68789944320 bytes (69 GB) copied, 2732.55 seconds, 25.2 MB/s
>>
>> and
>>
>> Root gershwin:[~] > dd if=/dev/sdj of=/dev/null bs=8192
>> 739200+0 records in
>> 739199+0 records out
>> 6055518208 bytes (6.1 GB) copied, 447.178 seconds, 13.5 MB/s
>>
>> 	without any trouble.
> 
> The speed can definitely be improved. Look at your network setup
> and use ping to try and get the network latency to a minimum.
> 
> # ping -A -s 8192 172.16.24.140
> ....
> --- 172.16.24.140 ping statistics ---
> 14058 packets transmitted, 14057 received, 0% packet loss, time 9988ms
> rtt min/avg/max/mdev = 0.234/0.268/2.084/0.041 ms, ipg/ewma 0.710/0.260 ms

gershwin:[~] > ping -A -s 8192 192.168.0.2
PING 192.168.0.2 (192.168.0.2) 8192(8220) bytes of data.
8200 bytes from 192.168.0.2: icmp_seq=1 ttl=64 time=0.693 ms
8200 bytes from 192.168.0.2: icmp_seq=2 ttl=64 time=0.595 ms
8200 bytes from 192.168.0.2: icmp_seq=3 ttl=64 time=0.583 ms
8200 bytes from 192.168.0.2: icmp_seq=4 ttl=64 time=0.589 ms
8200 bytes from 192.168.0.2: icmp_seq=5 ttl=64 time=0.580 ms
8200 bytes from 192.168.0.2: icmp_seq=6 ttl=64 time=0.594 ms
8200 bytes from 192.168.0.2: icmp_seq=7 ttl=64 time=0.580 ms
8200 bytes from 192.168.0.2: icmp_seq=8 ttl=64 time=0.592 ms
8200 bytes from 192.168.0.2: icmp_seq=9 ttl=64 time=0.589 ms
8200 bytes from 192.168.0.2: icmp_seq=10 ttl=64 time=0.571 ms
8200 bytes from 192.168.0.2: icmp_seq=11 ttl=64 time=0.588 ms
8200 bytes from 192.168.0.2: icmp_seq=12 ttl=64 time=0.580 ms
8200 bytes from 192.168.0.2: icmp_seq=13 ttl=64 time=0.587 ms

--- 192.168.0.2 ping statistics ---
13 packets transmitted, 13 received, 0% packet loss, time 2400ms
rtt min/avg/max/mdev = 0.571/0.593/0.693/0.044 ms, ipg/ewma 200.022/0.607 ms
gershwin:[~] >

	Both initiator and target are alone on a gigabit NIC (Tigon3). On 
target server, istd1 takes 100% of a CPU (and only one CPU, even my 
T1000 can simultaneous run 32 threads). I think the limitation comes 
from istd1.

> You want your avg ping time for 8192 byte payloads to be 300us or less.
> 
> 1000/.268 = 3731 IOPS @ 8k = 30 MB/s
> 
> If you use apps that do overlapping asynchronous IO you can see better
> numbers.

	Regards,

	JKB

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