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<div class="moz-cite-prefix">On 02/12/2015 10:58 PM, Punit Dambiwal
wrote:<br>
</div>
<blockquote
cite="mid:CAGZcrB=AVFY5mgbNq__BnGoRn4iFe-a_77_eN+5iC_46eeqrAA@mail.gmail.com"
type="cite">
<div dir="ltr">Hi,
<div><br>
</div>
<div>I have seen the gluster performance is dead slow on the
small files...even i am using the SSD....it's too bad
performance....even i am getting better performance in my SAN
with normal SATA disk...</div>
<div><br>
</div>
<div>I am using distributed replicated glusterfs with replica
count=2...i have all SSD disks on the brick...</div>
<div><br>
</div>
<div>
<p class="MsoNormal"><span
style="font-size:11pt;font-family:Menlo-Regular;color:black">root@vm3:~#
dd bs=64k count=4k
if=/dev/zero of=test oflag=dsync</span></p>
<p class="MsoNormal"><span
style="font-size:11pt;font-family:Menlo-Regular;color:black">4096+0
records in</span></p>
<p class="MsoNormal"><span
style="font-size:11pt;font-family:Menlo-Regular;color:black">4096+0
records out</span></p>
<p class="MsoNormal"><span
style="font-size:11pt;font-family:Menlo-Regular;color:black">268435456
bytes (268 MB) copied, 57.3145
s, 4.7 MB/s</span></p>
<p class="MsoNormal"><br>
</p>
<p class="MsoNormal"><span
style="font-size:11pt;font-family:Menlo-Regular;color:black">root@vm3:~#
dd bs=64k count=4k
if=/dev/zero of=test conv=fdatasync</span></p>
<p class="MsoNormal"><span
style="font-size:11pt;font-family:Menlo-Regular;color:black">4096+0
records in</span></p>
<p class="MsoNormal"><span
style="font-size:11pt;font-family:Menlo-Regular;color:black">4096+0
records out</span></p>
<p class="MsoNormal"><span
style="font-size:11pt;font-family:Menlo-Regular;color:black">268435456
bytes (268 MB) copied, 1.80093
s, 149 MB/s</span></p>
<p class="MsoNormal"><span
style="font-size:11pt;font-family:Menlo-Regular;color:black"><br>
</span></p>
<br>
</div>
</div>
</blockquote>
How small is your VM image? The image is the file that GlusterFS is
serving, not the small files within it. Perhaps the filesystem
you're using within your VM is inefficient with regard to how it
handles disk writes.<br>
<br>
I believe your concept of "small file" performance is misunderstood,
as is often the case with this phrase. The "small file" issue has to
do with the overhead of finding and checking the validity of any
file, but with a small file the percentage of time doing those
checks is proportionally greater. With your VM image, that file is
already open. There are no self-heal checks or lookups that are
happening in your tests, so that overhead is not the problem.<br>
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