unknown
1970-01-01 00:00:00 UTC
Hence for a RAID6 with 256KB of stripe size "I" should be 2560. Does it
mean that the "I" parameter is stripesize*number_of_data_disks? I mean, if
I have 16 data disks in a RAID6 and 1MB of stripe size, which should be the
"I" value?
On the other hand, yes, 2560 is a large full stripe but we are mostly
managing large files (hundred MBs and few GB), so I guess this is ok. Is
possible to check the minimum recommended file size for a configuration
like this? I would like to know it because we also have few storage pools
(less than 3% of the total) we a small file profile and I would like to fit
the disk configuration to its workload type.
with Scientific Linux 6. Then, how should I manage the XFS 'su' and 'sw'
parameters from the LVM2 configuration in order to ensure disk alignment in
order to have best performance?
Once again, thanks a lot for you help,
--
Marc Caubet Serrabou
PIC (Port d'Informació Científica)
Campus UAB, Edificio D
E-08193 Bellaterra, Barcelona
Tel: +34 93 581 33 22
Fax: +34 93 581 41 10
http://www.pic.es
Avis - Aviso - Legal Notice: http://www.ifae.es/legal.html
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<div dir="ltr">Hi Mike,<br><br>thanks a lot for your answer. <br><div class="gmail_extra"><br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div class="">
> Hi all,<br>
><br>
> I am trying to setup a storage pool with correct disk alignment and I hope<br>
> somebody can help me to understand some unclear parts to me when<br>
> configuring XFS over LVM2.<br>
><br>
> Actually we have few storage pools with the following settings each:<br>
><br>
> - LSI Controller with 3xRAID6<br>
> - Each RAID6 is configured with 10 data disks + 2 for double-parity.<br>
> - Each disk has a capacity of 4TB, 512e and physical sector size of 4K.<br>
> - 3x(10+2) configuration was considered in order to gain best performance<br>
> and data safety (less disks per RAID less probability of data corruption)<br>
<br>
</div>What is the chunk size used for these RAID6 devices?<br>
Say it is 256K, you have 10 data devices, so the full stripe would be<br>
2560K.<br></blockquote><div><br></div><div>Actually chunk size is 256KB (in a near future we will try 1MB as we are managing large files but actually we want to keep the current configuration of 256KB)<br></div><div><br>
</div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
Which version of lvm2 and kernel are you using? Newer versions support<br>
a striped LV stripesize that is not a power-of-2.<br></blockquote><div><br>Current LVM2 version is lvm2-2.02.100-8.el6.x86_64<br><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div class="">
> >
mean that the "I" parameter is stripesize*number_of_data_disks? I mean, if
I have 16 data disks in a RAID6 and 1MB of stripe size, which should be the
"I" value?
On the other hand, yes, 2560 is a large full stripe but we are mostly
managing large files (hundred MBs and few GB), so I guess this is ok. Is
possible to check the minimum recommended file size for a configuration
like this? I would like to know it because we also have few storage pools
(less than 3% of the total) we a small file profile and I would like to fit
the disk configuration to its workload type.
Hence, stripe of the 3 RAID6 in a LV.
minimum_io_size and optimal_io_size) by the striped LV.
But if not you definitely don't want to be trying to pierce through the
striped LV config to establish settings of the underlying RAID6. Each
layer in the stack should respect the layer beneath it. So, if the
striped LV is configured how you'd like, you should only concern
yourself with the limits that have been established for the topmost
striped LV that you're layering XFS on.
Current XFS package has the version xfsprogs-3.1.1-14.el6.x86_64 and comesAnd here is my first question: How can I check if the storage and the LV
are correctly aligned?
mkfs.xfs -d su=256k,sw=10 -l size=128m,lazy-count=1 /dev/dcvg_a/dcpool
So my second question is, are the above 'su' and 'sw' parameters correct
onare correctly aligned?
mkfs.xfs -d su=256k,sw=10 -l size=128m,lazy-count=1 /dev/dcvg_a/dcpool
So my second question is, are the above 'su' and 'sw' parameters correct
the current LV configuration? If not, which values should I have and why?
AFAIK su is the stripe size configured in the controller side, but in
thisAFAIK su is the stripe size configured in the controller side, but in
case we have a LV. Also, sw is the number of data disks in a RAID, but
again, we have a LV with 3 stripes, and I am not sure if the number of
dataagain, we have a LV with 3 stripes, and I am not sure if the number of
disks should be 30 instead.
Newer versions of mkfs.xfs _should_ pick up the hints exposed (asminimum_io_size and optimal_io_size) by the striped LV.
But if not you definitely don't want to be trying to pierce through the
striped LV config to establish settings of the underlying RAID6. Each
layer in the stack should respect the layer beneath it. So, if the
striped LV is configured how you'd like, you should only concern
yourself with the limits that have been established for the topmost
striped LV that you're layering XFS on.
with Scientific Linux 6. Then, how should I manage the XFS 'su' and 'sw'
parameters from the LVM2 configuration in order to ensure disk alignment in
order to have best performance?
Once again, thanks a lot for you help,
--
Marc Caubet Serrabou
PIC (Port d'Informació Científica)
Campus UAB, Edificio D
E-08193 Bellaterra, Barcelona
Tel: +34 93 581 33 22
Fax: +34 93 581 41 10
http://www.pic.es
Avis - Aviso - Legal Notice: http://www.ifae.es/legal.html
--001a11c339e6b2f04f04f8e01f9e
Content-Type: text/html; charset=UTF-8
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<div dir="ltr">Hi Mike,<br><br>thanks a lot for your answer. <br><div class="gmail_extra"><br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div class="">
> Hi all,<br>
><br>
> I am trying to setup a storage pool with correct disk alignment and I hope<br>
> somebody can help me to understand some unclear parts to me when<br>
> configuring XFS over LVM2.<br>
><br>
> Actually we have few storage pools with the following settings each:<br>
><br>
> - LSI Controller with 3xRAID6<br>
> - Each RAID6 is configured with 10 data disks + 2 for double-parity.<br>
> - Each disk has a capacity of 4TB, 512e and physical sector size of 4K.<br>
> - 3x(10+2) configuration was considered in order to gain best performance<br>
> and data safety (less disks per RAID less probability of data corruption)<br>
<br>
</div>What is the chunk size used for these RAID6 devices?<br>
Say it is 256K, you have 10 data devices, so the full stripe would be<br>
2560K.<br></blockquote><div><br></div><div>Actually chunk size is 256KB (in a near future we will try 1MB as we are managing large files but actually we want to keep the current configuration of 256KB)<br></div><div><br>
</div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
Which version of lvm2 and kernel are you using? Newer versions support<br>
a striped LV stripesize that is not a power-of-2.<br></blockquote><div><br>Current LVM2 version is lvm2-2.02.100-8.el6.x86_64<br><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div class="">
> >