10:52 p.m.
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What you mentioned is a specific case and not a generic situation. The
main point there is that RAID 5 or 6 impacts write performance compared
when you write to only 2 given disks at a time. That was the comparison
made.
Fernando
On 07/08/2017 16:49, Fabrice Bacchella wrote:
> Le 7 août 2017 à 17:41, FERNANDO FREDIANI <fernando.frediani(a)upx.com
> <mailto:fernando.frediani@upx.com>> a écrit :
>
> Yet another downside of having a RAID (specially RAID 5 or 6) is that
> it reduces considerably the write speeds as each group of disks will
> end up having the write speed of a single disk as all other disks of
> that group have to wait for each other to write as well.
>
That's not true if you have medium to high range hardware raid. For
example, HP Smart Array come with a flash cache of about 1 or 2 Gb
that hides that from the OS.
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<p>What you mentioned is a specific case and not a generic
situation. The main point there is that RAID 5 or 6 impacts write
performance compared when you write to only 2 given disks at a
time. That was the comparison made.<br>
</p>
<p>Fernando<br>
</p>
<br>
<div class="moz-cite-prefix">On 07/08/2017 16:49, Fabrice Bacchella
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:034E384B-4B32-4FBC-A760-404EB38EBC86@orange.fr">
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charset=utf-8">
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<blockquote type="cite" class="">
<div class="">Le 7 août 2017 à 17:41, FERNANDO FREDIANI
<<a
href="mailto:fernando.frediani@upx.com" class=""
moz-do-not-send="true">fernando.frediani(a)upx.com</a>&gt; a
écrit :</div>
<br class="Apple-interchange-newline">
</blockquote>
<br class="">
<blockquote type="cite" class="">
<div class="">
<p style="font-family: Helvetica; font-size: 12px;
font-style: normal; font-variant-caps: normal;
font-weight: normal; letter-spacing: normal; orphans:
auto; text-align: start; text-indent: 0px; text-transform:
none; white-space: normal; widows: auto; word-spacing:
0px; -webkit-text-stroke-width: 0px; background-color:
rgb(255, 255, 255);" class="">Yet another downside of
having a RAID (specially RAID 5 or 6) is that it reduces
considerably the write speeds as each group of disks will
end up having the write speed of a single disk as all
other disks of that group have to wait for each other to
write as well.<br class="">
</p>
</div>
</blockquote>
<br class="">
</div>
That's not true if you have medium to high range hardware raid.
For example, HP Smart Array come with a flash cache of about 1 or
2 Gb that hides that from the OS.
</blockquote>
<br>
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