AW: AW: [Ocfs-users] OCFS 1.0.9-6 performance with EVA 6000 Storage

Wed Jun 2 12:09:08 CDT 2004

Ok,

So in Jeram's case he still have 1000 I/O's per second due to hartbeat (5
nodes times 4 i/o per second per node times 51 mounts). This will not
exhaust the FC infrastructure, but probably the disk array, as stated
before.

If I'm not wrong, you can usually not exhaust a disk for more than 30 - 50
I/O's per second (depending on many things, sometimes up to 120 I/O's, but
not much more). Well, the controller is probably configured "write behind",
which is not really touching the disks all the time, so the controller
should probably be able to handle it. Also some vendors turn off the on disk
write cache (e.g Sun) for security reasons, which will keep down the per
disk I/O (at least for writes) to a minimum.

Hmmm... feels like I'm wandering off from the topic.

The problem with hartbeating is that one would probably like to keep it down
to a minimum as well as ensuring availability. Also, health checking a
larger number of volumes/luns which reside on the same physical storage is
redundant, but inevitable since the underlaying hardware structure is hidden
from the OS.

I assume it will be interesting to see the (configurable) solution for this
in the upcoming version. Or are there pointers on where I can do some
reading on this already (source code or similar in "worst case")? 

As such, 51 mountpoints is not That many in a large environment, especially
when talking about the limitations that do exist when using OCFS.

Thanks,
//magnus

-----Ursprüngliche Nachricht-----
Von: Wim Coekaerts [mailto:wim.coekaerts at oracle.com] 
Gesendet: Mittwoch, 2. Juni 2004 10:31
An: Magnus Lubeck
Cc: ocfs-users at oss.oracle.com
Betreff: Re: AW: [Ocfs-users] OCFS 1.0.9-6 performance with EVA 6000 Storage

Hi Magnus

actually no it's not That bad
it's 1 read and 1 write, we do a 16kb read, not 32 sepereate reads.
so you have 4 read/write transactiosn per node per second per lun

eva is the replacement (new version) of msa1000's

Wim

On Wed, Jun 02, 2004 at 10:09:58AM +0200, Magnus Lubeck wrote:
> Hi all,
> 
> Sorry to break in, but I find this thread a bit interesting.
> 
> Jeram: I'm not very familiar with HP storage and cannot find too much info
> on the EVA 6000 array. Is it related to the EVA 5000 somehow, or is it a
NAS
> array?
> 
> In any case, how is the array configured. If the algorithm for hartbeat is
> as described earlier (36 sector reads and one write per second (per
> host???)) then you have some 37 I/O's per second per volume, which in your
> case is close to 2000 I/O's per second PER box, which could easily be
close
> to 10k I/O per second if the hartbeat is per node.
> 
> Am I right in this assumption? In Jeram's case, having 5 nodes, 51 mounts.
> Would the hartbeat generate 2k or 10k I/O's?
> 
> In any case, if I'm correct, this would then (as Wim states) be somewhat
> exhausting for most parts of the storage system. Even 2000 I/O's per
second
> could easily exhaust a LUN group in most arrays.
> 
> Thanks for an interesting discussion.
> 
> //magnus
> 
> -----Urspr?ngliche Nachricht-----
> Von: ocfs-users-bounces at oss.oracle.com
> [mailto:ocfs-users-bounces at oss.oracle.com] Im Auftrag von Jeram
> Gesendet: Mittwoch, 2. Juni 2004 03:53
> An: Wim Coekaerts
> Cc: Sunil Mushran; ocfs-users at oss.oracle.com
> Betreff: RE: [Ocfs-users] OCFS 1.0.9-6 performance with EVA 6000 Storage
> 
> Hi Wim...
> 
> Ok Then...I will try .11 first, and awaiting for .12,meanwhile I am
waiting
> for HP Engineers whether they have any good idea from eva6000 point of
> view..
> 
> Thanks a lot for your informations.
> Rgds/Jeram
> 
> -----Original Message-----
> From: Wim Coekaerts [mailto:wim.coekaerts at oracle.com]
> Sent: Wednesday, June 02, 2004 8:41 AM
> To: Jeram
> Cc: Sunil Mushran; ocfs-users at oss.oracle.com
> Subject: Re: [Ocfs-users] OCFS 1.0.9-6 performance with EVA 6000 Storage
> 
> 
> 1.0.11 won't change amount of io. if you already have io problems you
> have to use .12, which should be out any day..  
> 
> 
> On Wed, Jun 02, 2004 at 08:35:49AM +0700, Jeram wrote:
> > Hi Sunil...
> > 
> > Thanks for your response, I will try to use 1.0.11, and observe the
> > performance...
> > 
> > Rgds/Jeram
> > 
> > -----Original Message-----
> > From: Sunil Mushran [mailto:Sunil.Mushran at oracle.com]
> > Sent: Wednesday, June 02, 2004 8:30 AM
> > To: Jeram
> > Cc: ocfs-users at oss.oracle.com; ocfs-devel at oss.oracle.com
> > Subject: Re: [Ocfs-users] OCFS 1.0.9-6 performance with EVA 6000 Storage
> > 
> > 
> > Heartbeating in ocfs is currently per volume. The nmthread reads 36
> > sectors and writes 1 sector every second or so. The io in vmstat you see
> > is due to heartbeat.
> > 
> > As far as the mount is concerned, the mount thread waits for the
> > nmthread the stabilize, 10 secs or so.
> > 
> > We are working on making the heartbeat configurable. 1.0.12 will have
> > some stuff regarding that.... hb and timeout values. It will not be
> > activated by default. We are still working out the details. That will
> > reduce the hb related io.
> > 
> > If you want to use 51 mounts, make sure your hardware can handle the io.
> > For e.g., if you see ocfs msgs like, "Removing nodes" and "Adding nodes"
> > without a node performing any mount/umount, you have a problem. In
> > anycase, you should use 1.0.11 at the least. In 1.0.10, we doubled the
> > timeout from 1.0.9.
> > 
> > Hope this helps.
> > Sunil
> > 
> > On Tue, 2004-06-01 at 18:04, Jeram wrote:
> > > Dear All...
> > > 
> > > I need some information regarding OCFS performance in my Linux Box,
> > herewith
> > > is my environment details :
> > > 1. We are using RHAS 2.1 with kernel 2.4.9-e.27 Enterprise
> > > 2. OCFS version : 2.4.9-e-enterprise-1.0.9-6
> > > 3. Oracle RDBMS : 9.2.0.4 RAC with 5 Nodes
> > > 4. Storage = EVA 6000 with 8 TB SIZE
> > > 5. We have 1 DiskGroup and 51 LUNs configured in EVA6000.
> > > My Question is :
> > > 1. It takes arround 15 minutes to mount arround 51 ocfs file system,
is
> > this
> > > a normal situation?
> > > 2. I monitor the OS using VMSTAT without starting the RAC server,
column
> > IO
> > > (bo and bi) it's giving 3 digits value continuously, then I unmount
all
> > the
> > > OCFS filesystem, again monitor the IO using VMSTAT,  column IO (bo and
> bi)
> > > it's giving 1 digits value, any idea why this is happen?
> > > I have raised this issue to HP engineers who provide the HW, have not
> got
> > > the answer yet.
> > > Thanks in advance
> > > Rgds/Jeram  
> > >  
> > > 
> > > 
> > > 
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> > > Ocfs-users at oss.oracle.com
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