<div dir="ltr">LVM is also good if you want to add ssd cache. It is more flexible and easier to manage and expand than bcache.<br></div><div class="gmail_extra"><br><div class="gmail_quote">On 11 October 2017 at 04:00, Mohammed Rafi K C <span dir="ltr"><<a href="mailto:rkavunga@redhat.com" target="_blank">rkavunga@redhat.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
Volumes are aggregation of bricks, so I would consider bricks as a<br>
unique entity here rather than volumes. Taking the constraints from the<br>
blog [1].<br>
<br>
* All bricks should be carved out from an independent thinly provisioned<br>
logical volume (LV). In other words, no two brick should share a common<br>
LV. More details about thin provisioning and thin provisioned snapshot<br>
can be found here.<br>
* This thinly provisioned LV should only be used for forming a brick.<br>
* Thin pool from which the thin LVs are created should have sufficient<br>
space and also it should have sufficient space for pool metadata.<br>
<br>
You can refer the blog post here [1].<br>
<br>
[1] : <a href="http://rajesh-joseph.blogspot.in/p/gluster-volume-snapshot-howto.html" rel="noreferrer" target="_blank">http://rajesh-joseph.blogspot.<wbr>in/p/gluster-volume-snapshot-<wbr>howto.html</a><br>
<br>
Regards<br>
Rafi KC<br>
<div class="HOEnZb"><div class="h5"><br>
<br>
On 10/11/2017 01:23 PM, ML wrote:<br>
> Thanks Rafi, that's understood now :)<br>
><br>
> I'm considering to deploy gluster on a 4 x 40 TB bricks, do you think<br>
> it would better to make 1 LVM partition for each Volume I need or to<br>
> make one Big LVM partition and start multiple volumes on it ?<br>
><br>
> We'll store mostly big files (videos) on this environement.<br>
><br>
><br>
><br>
><br>
> Le 11/10/2017 à 09:34, Mohammed Rafi K C a écrit :<br>
>><br>
>> On 10/11/2017 12:20 PM, ML wrote:<br>
>>> Hi everyone,<br>
>>><br>
>>> I've read on the gluster & redhat documentation, that it seems<br>
>>> recommended to use XFS over LVM before creating & using gluster<br>
>>> volumes.<br>
>>><br>
>>> Sources :<br>
>>> <a href="https://access.redhat.com/documentation/en-US/Red_Hat_Storage/3/html/Administration_Guide/Formatting_and_Mounting_Bricks.html" rel="noreferrer" target="_blank">https://access.redhat.com/<wbr>documentation/en-US/Red_Hat_<wbr>Storage/3/html/Administration_<wbr>Guide/Formatting_and_Mounting_<wbr>Bricks.html</a><br>
>>><br>
>>><br>
>>> <a href="http://gluster.readthedocs.io/en/latest/Administrator%20Guide/Setting%20Up%20Volumes/" rel="noreferrer" target="_blank">http://gluster.readthedocs.io/<wbr>en/latest/Administrator%<wbr>20Guide/Setting%20Up%<wbr>20Volumes/</a><br>
>>><br>
>>><br>
>>><br>
>>> My point is : do we really need LVM ?<br>
>> This recommendations was added after gluster-snapshot. Gluster snapshot<br>
>> relays on LVM snapshot. So if you start with out lvm, in future if you<br>
>> want to use snapshot then it would be difficult, hence the<br>
>> recommendation to use xfs on top of lvm.<br>
>><br>
>><br>
>> Regards<br>
>> Rafi KC<br>
>><br>
>>> For example , on a dedicated server with disks & partitions that will<br>
>>> not change of size, it doesn't seems necessary to use LVM.<br>
>>><br>
>>> I can't understand clearly wich partitioning strategy would be the<br>
>>> best for "static size" hard drives :<br>
>>><br>
>>> 1 LVM+XFS partition = multiple gluster volumes<br>
>>> or 1 LVM+XFS partition = 1 gluster volume per LVM+XFS partition<br>
>>> or 1 XFS partition = multiple gluster volumes<br>
>>> or 1 XFS partition = 1 gluster volume per XFS partition<br>
>>><br>
>>> What do you use on your servers ?<br>
>>><br>
>>> Thanks for your help! :)<br>
>>><br>
>>> Quentin<br>
>>><br>
>>><br>
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><br>
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</div></div></blockquote></div><br></div>