Re: [lustre-discuss] [EXTERNAL] Mounting lustre on block device

2023-04-05 Thread Andreas Dilger via lustre-discuss 


On Mar 16, 2023, at 17:02, Jeff Johnson 
mailto:jeff.john...@aeoncomputing.com>> wrote:

If you *really* want a block device on a client that resides in Lustre you 
*could* create a file in Lustre and then make that file a loopback device with 
losetup. Of course, your mileage will vary *a lot* based on use case, access, 
underlying LFS configuration.

dd if=/dev/zero of=/my_lustre_mountpoint/some_subdir/big_raw_file bs=1048576 
count=10
losetup -f /my_lustre_mountpoint/some_subdir/big_raw_file
*assuming loop0 is created*
some_fun_command /dev/loop0

Note with ldiskfs backends you can use "fallocate -l 10M 
/my_lustre_mountpoint/some_subdir/big_raw_file" to reserve the space.

Alternately, if you have flash-based OSTs you could truncate a sparse file to 
the full size ("truncate -S 10M ...") and format that, which will not 
consume as much space but will generate more random allocation on the OSTs.

Disclaimer: Just because you *can* do this, doesn't necessarily mean it is a 
good idea

We saw a good performance boost with ext4 images on Lustre holding many small 
files (CCI).  Also, I recall some customers in the past using ext2 or ext4 
images effectively to aggregate many small files for read-only use on compute 
nodes.

Cheers, Andreas


On Thu, Mar 16, 2023 at 3:29 PM Mohr, Rick via lustre-discuss 
mailto:lustre-discuss@lists.lustre.org>> wrote:
Are you asking if you can mount Lustre on a client so that it shows up as a 
block device?  If so, the answer to that is you can't.  Lustre does not appear 
as a block device to the clients.

-Rick



On 3/16/23, 3:44 PM, "lustre-discuss on behalf of Shambhu Raje via 
lustre-discuss" 
mailto:lustre-discuss-boun...@lists.lustre.org>
 
>
 on behalf of 
lustre-discuss@lists.lustre.org 
>>
 wrote:


When we mount a lustre file system on client, the lustre file system does not 
use block device on client side. Instead it uses virtual file system namespace. 
Mounting point will not be shown when we do 'lsblk'. As it only show on 'df-hT'.


How can we mount lustre file system on block such that when we write something 
with lusterfs then it can be shown in block device??
Can share command??











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--
--
Jeff Johnson
Co-Founder
Aeon Computing

jeff.john...@aeoncomputing.com
www.aeoncomputing.com
t: 858-412-3810 x1001   f: 858-412-3845
m: 619-204-9061

4170 Morena Boulevard, Suite C - San Diego, CA 92117

High-Performance Computing / Lustre Filesystems / Scale-out Storage
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Cheers, Andreas
--
Andreas Dilger
Lustre Principal Architect
Whamcloud







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Re: [lustre-discuss] [EXTERNAL] Mounting lustre on block device

2023-03-16 Thread Jeff Johnson 
If you *really* want a block device on a client that resides in Lustre you
*could* create a file in Lustre and then make that file a loopback device
with losetup. Of course, your mileage will vary *a lot* based on use case,
access, underlying LFS configuration.

dd if=/dev/zero
of=/my_lustre_mountpoint/some_subdir/big_raw_file bs=1048576 count=10
losetup -f /my_lustre_mountpoint/some_subdir/big_raw_file
*assuming loop0 is created*
some_fun_command /dev/loop0

Disclaimer: Just because you *can* do this, doesn't necessarily mean it is
a good idea



On Thu, Mar 16, 2023 at 3:29 PM Mohr, Rick via lustre-discuss <
lustre-discuss@lists.lustre.org> wrote:

> Are you asking if you can mount Lustre on a client so that it shows up as
> a block device?  If so, the answer to that is you can't.  Lustre does not
> appear as a block device to the clients.
>
> -Rick
>
>
>
> On 3/16/23, 3:44 PM, "lustre-discuss on behalf of Shambhu Raje via
> lustre-discuss"  lustre-discuss-boun...@lists.lustre.org> on behalf of
> lustre-discuss@lists.lustre.org >
> wrote:
>
>
> When we mount a lustre file system on client, the lustre file system does
> not use block device on client side. Instead it uses virtual file system
> namespace. Mounting point will not be shown when we do 'lsblk'. As it only
> show on 'df-hT'.
>
>
> How can we mount lustre file system on block such that when we write
> something with lusterfs then it can be shown in block device??
> Can share command??
>
>
>
>
>
>
>
>
>
>
>
> ___
> lustre-discuss mailing list
> lustre-discuss@lists.lustre.org
> http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org
>


-- 
--
Jeff Johnson
Co-Founder
Aeon Computing

jeff.john...@aeoncomputing.com
www.aeoncomputing.com
t: 858-412-3810 x1001   f: 858-412-3845
m: 619-204-9061

4170 Morena Boulevard, Suite C - San Diego, CA 92117

High-Performance Computing / Lustre Filesystems / Scale-out Storage
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Re: [lustre-discuss] [EXTERNAL] Mounting lustre on block device

2023-03-16 Thread Mohr, Rick via lustre-discuss 
Are you asking if you can mount Lustre on a client so that it shows up as a 
block device?  If so, the answer to that is you can't.  Lustre does not appear 
as a block device to the clients.

-Rick



On 3/16/23, 3:44 PM, "lustre-discuss on behalf of Shambhu Raje via 
lustre-discuss" mailto:lustre-discuss-boun...@lists.lustre.org> on behalf of 
lustre-discuss@lists.lustre.org > wrote:


When we mount a lustre file system on client, the lustre file system does not 
use block device on client side. Instead it uses virtual file system namespace. 
Mounting point will not be shown when we do 'lsblk'. As it only show on 'df-hT'.


How can we mount lustre file system on block such that when we write something 
with lusterfs then it can be shown in block device??
Can share command??











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