[OpenAFS] ramdisk Problems under 2.6 kernel

ted creedon tcreedon@easystreet.com
Wed, 6 Jul 2005 07:47:21 -0700


This is a multi-part message in MIME format.

------=_NextPart_000_02BA_01C581FE.F246A700
Content-Type: text/plain;
	charset="us-ascii"
Content-Transfer-Encoding: 7bit

Precisely what I do for a test system. Loopbacks work fine. 
 
Any serious performance hits with loopback devices on /dev/shm?
 
tedc

  _____  

From: Sven Oehme [mailto:oehmes@de.ibm.com] 
Sent: Wednesday, July 06, 2005 12:52 AM
To: ted creedon
Cc: openafs-info@openafs.org
Subject: RE: [OpenAFS] ramdisk Problems under 2.6 kernel



because you don't reach high enough throughput with memcache. 
with memcache i am limited to around 25 mb/sec. with disk cache i reach 30
mb/sec which is the local drive. 
with a formatted ramdisk as diskcache i get 50 - 60 mb/sec 
so lets see if we can get a fix for /dev/shm ... because ramdisk is anyway
deprecated. 
btw. the workaround is to create a file in /dev/shm with dd, format it ,
mount it as loopdevice :-) 

Sven 




"ted creedon" <tcreedon@easystreet.com> 
Sent by: openafs-info-admin@openafs.org 


05/07/2005 21:59 


To

cc
<openafs-info@openafs.org> 

Subject
RE: [OpenAFS] ramdisk Problems under 2.6 kernel

	




Why is that? 
  
tedc 


  _____  

From: openafs-info-admin@openafs.org [mailto:openafs-info-admin@openafs.org]
On Behalf Of Sven Oehme
Sent: Tuesday, July 05, 2005 10:08 AM
To: Ryan Underwood
Cc: openafs-info@openafs.org
Subject: Re: [OpenAFS] ramdisk Problems under 2.6 kernel


it's simple , it's to slow .. 

Sven



Ryan Underwood <nemesis-lists@icequake.net> 
Sent by: openafs-info-admin@openafs.org 


05/07/2005 17:46 




To
openafs-info@openafs.org 

cc

Subject
Re: [OpenAFS] ramdisk Problems under 2.6 kernel


	






On Mon, Jul 04, 2005 at 11:38:14PM +0200, Sven Oehme wrote:
>    Hi ,
> 
>    we have identified some Ramdisk Problems under 2.6 kernels compiled on
>    i386
>    has anybody ever tried using tmpfs for the cache disk ?

What about using -memcache instead?

-- 
Ryan Underwood, <nemesis@icequake.net>
_______________________________________________
OpenAFS-info mailing list
OpenAFS-info@openafs.org
https://lists.openafs.org/mailman/listinfo/openafs-info



------=_NextPart_000_02BA_01C581FE.F246A700
Content-Type: text/html;
	charset="us-ascii"
Content-Transfer-Encoding: quoted-printable

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Dus-ascii">
<META content=3D"MSHTML 6.00.2900.2668" name=3DGENERATOR></HEAD>
<BODY>
<DIV dir=3Dltr align=3Dleft><FONT face=3DArial color=3D#0000ff =
size=3D2><SPAN=20
class=3D011214514-06072005>Precisely what I do for a test system. =
Loopbacks work=20
fine. </SPAN></FONT></DIV>
<DIV dir=3Dltr align=3Dleft><FONT face=3DArial color=3D#0000ff =
size=3D2><SPAN=20
class=3D011214514-06072005></SPAN></FONT>&nbsp;</DIV>
<DIV dir=3Dltr align=3Dleft><FONT face=3DArial color=3D#0000ff =
size=3D2><SPAN=20
class=3D011214514-06072005>Any serious performance hits with loopback =
devices on=20
/dev/shm?</SPAN></FONT></DIV>
<DIV dir=3Dltr align=3Dleft><FONT face=3DArial color=3D#0000ff =
size=3D2><SPAN=20
class=3D011214514-06072005></SPAN></FONT>&nbsp;</DIV>
<DIV dir=3Dltr align=3Dleft><FONT face=3DArial color=3D#0000ff =
size=3D2><SPAN=20
class=3D011214514-06072005>tedc</SPAN></FONT></DIV><BR>
<DIV class=3DOutlookMessageHeader lang=3Den-us dir=3Dltr align=3Dleft>
<HR tabIndex=3D-1>
<FONT face=3DTahoma size=3D2><B>From:</B> Sven Oehme =
[mailto:oehmes@de.ibm.com]=20
<BR><B>Sent:</B> Wednesday, July 06, 2005 12:52 AM<BR><B>To:</B> ted=20
creedon<BR><B>Cc:</B> openafs-info@openafs.org<BR><B>Subject:</B> RE: =
[OpenAFS]=20
ramdisk Problems under 2.6 kernel<BR></FONT><BR></DIV>
<DIV></DIV><BR><FONT face=3Dsans-serif size=3D2>because you don't reach =
high enough=20
throughput with memcache. </FONT><BR><FONT face=3Dsans-serif =
size=3D2>with memcache=20
i am limited to around 25 mb/sec. with disk cache i reach 30 mb/sec =
which is the=20
local drive.</FONT> <BR><FONT face=3Dsans-serif size=3D2>with a =
formatted ramdisk as=20
diskcache i get 50 - 60 mb/sec</FONT> <BR><FONT face=3Dsans-serif =
size=3D2>so lets=20
see if we can get a fix for /dev/shm ... because ramdisk is anyway =
deprecated.=20
</FONT><BR><FONT face=3Dsans-serif size=3D2>btw. the workaround is to =
create a file=20
in /dev/shm with dd, format it , mount it as loopdevice :-)</FONT> =
<BR><BR><FONT=20
face=3Dsans-serif size=3D2>Sven</FONT> <BR><BR><BR><BR>
<TABLE width=3D"100%">
  <TBODY>
  <TR vAlign=3Dtop>
    <TD width=3D"40%"><FONT face=3Dsans-serif size=3D1><B>"ted creedon"=20
      &lt;tcreedon@easystreet.com&gt;</B> </FONT><BR><FONT =
face=3Dsans-serif=20
      size=3D1>Sent by: openafs-info-admin@openafs.org</FONT>=20
      <P><FONT face=3Dsans-serif size=3D1>05/07/2005 21:59</FONT> </P>
    <TD width=3D"59%">
      <TABLE width=3D"100%">
        <TBODY>
        <TR>
          <TD>
            <DIV align=3Dright><FONT face=3Dsans-serif =
size=3D1>To</FONT></DIV>
          <TD vAlign=3Dtop>
        <TR>
          <TD>
            <DIV align=3Dright><FONT face=3Dsans-serif =
size=3D1>cc</FONT></DIV>
          <TD vAlign=3Dtop><FONT face=3Dsans-serif=20
            size=3D1>&lt;openafs-info@openafs.org&gt;</FONT>=20
        <TR>
          <TD>
            <DIV align=3Dright><FONT face=3Dsans-serif =
size=3D1>Subject</FONT></DIV>
          <TD vAlign=3Dtop><FONT face=3Dsans-serif size=3D1>RE: =
[OpenAFS] ramdisk=20
            Problems under 2.6 kernel</FONT></TR></TBODY></TABLE><BR>
      <TABLE>
        <TBODY>
        <TR vAlign=3Dtop>
          <TD>
          =
<TD></TR></TBODY></TABLE><BR></TR></TBODY></TABLE><BR><BR><BR><FONT =
face=3DArial=20
color=3Dblue size=3D2>Why is that?</FONT> <BR><FONT =
size=3D3>&nbsp;</FONT> <BR><FONT=20
face=3DArial color=3Dblue size=3D2>tedc</FONT> <BR><BR>
<HR>
<FONT face=3DTahoma size=3D2><B>From:</B> openafs-info-admin@openafs.org =

[mailto:openafs-info-admin@openafs.org] <B>On Behalf Of </B>Sven=20
Oehme<B><BR>Sent:</B> Tuesday, July 05, 2005 10:08 AM<B><BR>To:</B> Ryan =

Underwood<B><BR>Cc:</B> openafs-info@openafs.org<B><BR>Subject:</B> Re:=20
[OpenAFS] ramdisk Problems under 2.6 kernel</FONT><FONT=20
size=3D3><BR></FONT><BR><FONT face=3Dsans-serif size=3D2><BR>it's simple =
, it's to=20
slow ..</FONT><FONT size=3D3> <BR></FONT><FONT face=3Dsans-serif=20
size=3D2><BR>Sven</FONT><FONT size=3D3><BR><BR><BR></FONT>
<TABLE width=3D"100%">
  <TBODY>
  <TR vAlign=3Dtop>
    <TD width=3D"44%"><FONT face=3Dsans-serif size=3D1><B>Ryan Underwood =

      &lt;nemesis-lists@icequake.net&gt;</B> <BR>Sent by:=20
      openafs-info-admin@openafs.org</FONT><FONT size=3D3> </FONT>
      <P><FONT face=3Dsans-serif size=3D1>05/07/2005 17:46</FONT><FONT =
size=3D3>=20
      </FONT></P>
    <TD width=3D"55%"><BR>
      <TABLE width=3D"100%">
        <TBODY>
        <TR>
          <TD width=3D"18%">
            <DIV align=3Dright><FONT face=3Dsans-serif =
size=3D1>To</FONT></DIV>
          <TD vAlign=3Dtop width=3D"81%"><FONT face=3Dsans-serif=20
            size=3D1>openafs-info@openafs.org</FONT><FONT size=3D3> =
</FONT>
        <TR>
          <TD>
            <DIV align=3Dright><FONT face=3Dsans-serif =
size=3D1>cc</FONT></DIV>
          <TD vAlign=3Dtop>
        <TR>
          <TD>
            <DIV align=3Dright><FONT face=3Dsans-serif =
size=3D1>Subject</FONT></DIV>
          <TD vAlign=3Dtop><FONT face=3Dsans-serif size=3D1>Re: =
[OpenAFS] ramdisk=20
            Problems under 2.6 =
kernel</FONT></TR></TBODY></TABLE><BR><BR>
      <TABLE width=3D"100%">
        <TBODY>
        <TR vAlign=3Dtop>
          <TD width=3D"49%">
          <TD =
width=3D"50%"></TR></TBODY></TABLE><BR></TR></TBODY></TABLE><BR><FONT=20
size=3D3><BR><BR></FONT><FONT size=3D2><TT><BR><BR>On Mon, Jul 04, 2005 =
at=20
11:38:14PM +0200, Sven Oehme wrote:<BR>&gt; &nbsp; &nbsp;Hi ,<BR>&gt; =
<BR>&gt;=20
&nbsp; &nbsp;we have identified some Ramdisk Problems under 2.6 kernels =
compiled=20
on<BR>&gt; &nbsp; &nbsp;i386<BR>&gt; &nbsp; &nbsp;has anybody ever tried =
using=20
tmpfs for the cache disk ?<BR><BR>What about using -memcache =
instead?<BR><BR>--=20
<BR>Ryan Underwood,=20
&lt;nemesis@icequake.net&gt;<BR>_________________________________________=
______<BR>OpenAFS-info=20
mailing=20
list<BR>OpenAFS-info@openafs.org<BR>https://lists.openafs.org/mailman/lis=
tinfo/openafs-info</TT></FONT><FONT=20
size=3D3><BR></FONT><BR></BODY></HTML>

------=_NextPart_000_02BA_01C581FE.F246A700--