Ake,
in this particular case I can answer your question in detail.
Before SFAOS 12.1 (IIRC) the /sys/block/*/queue/rotational setting is set from
userspace at mount time via a udev script, and the Lustre detection of
"rotational=0" could be racy. Newer versions of SFAOS (12.1+) set the
On 5/20/22 09:53, Andreas Dilger via lustre-discuss wrote:
To elaborate a bit on Patrick's answer, there is no mechanism to do this on the
*client*, because the performance difference between client RAM and server
storage is still fairly significant, especially if the application is doing
y marginal if
> we're just doing buffered I/O then forcing the data out - it will reduce
> memory usage but it won't improve performance.
>
> -Patrick
>
> From: John Bauer
> Sent: Thursday, May 19, 2022 1:16 PM
> To: Patrick Farrell ; lustre-discuss@lists.lustre.org
>
Farrell ; lustre-discuss@lists.lustre.org
Subject: Re: [lustre-discuss] Avoiding system cache when using ssd pfl extent
Pat,
No, not in general. It just seems that if one is storing data on an SSD it
should be optional to have it not stored in memory ( why store in 2 fast
mediums ).
O_DIRECT
Pat,
No, not in general. It just seems that if one is storing data on an
SSD it should be optional to have it not stored in memory ( why store in
2 fast mediums ).
O_DIRECT is not of value as that would apply to all extents, whether on
SSD on HDD. O_DIRECT on Lustre has been problematic
No, and I'm not sure I agree with you at first glance.
Is this just generally an idea that data stored on SSD should not be in RAM?
If so, there's no mechanism for that other than using direct I/O.
-Patrick
From: lustre-discuss on behalf of
John Bauer
Sent:
