Hi, before i start i have to apologize for my bad English, i'm not a native english speaker.
i'm using LizardFS for my servers which one cluster uses HDD as storage and the other one uses SSD.
i was testing the performance of I/O with the dd command.
when i test the performance of the cluster using HDD storage, the results are just fine, but when i test the other cluster which uses SSD the read and write performances are way too slow.
common configs :
1 master server
2 chunk servers
the dd commands:
for write ==>
dd if=/dev/zero/ of=/mnt/lizardfs/TEST.img bs=2G count=1 oflag=dsync
for read ==>
echo 3 | tee /proc/sys/vm/drop_caches ; time dd if=/mnt/lizardfs/TEST.img of=/dev/null bs=BESTFIT_NUMBER
the performance for the HDD cluster:
write ==> around 25 MB/s
read ==> around 270 MB/s
the perfomance for the SSD cluster:
read ==> around 36 MB/s
write ==> around 16 MB/s
the CGI server shows that both SSD and HDD are performing at full speed.
for SSD it shows :
read ==> around 680 MB/s
write ==> 94 MB/s
things i've tested but yet not solved the issue: