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<p class="MsoNormal">We have been using ZFS on our LFS for about the last 7 years. Back then, we were using ZFS 0.7 and lustre 2.10 and there was a significant decrease in metadata performance compared to ldiskfs. Most of our workflows at the time didn’t
need a lot of metadata performance and so we were OK with the hit. In the meantime, we’ve had more small file I/O workflows come online and have been more focused on getting better metadata performance. About 2 years ago we upgraded the LFS to ZFS 2.0 and
lustre 2.14 and saw a big improvement in ZFS metadata performance, although still not as good as ldiskfs or even straight NFS. Our setup still shows a bit faster MDT performance with ldiskfs but the gap is now ~10% rather than about a factor of 2 from the
early life of this LFS. So bottom line, our experience shows that the difference between the two is a lot less than it used to be but ZFS still is slower than ldiskfs.
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<p class="MsoNormal"><b><span style="font-size:12.0pt;color:black">From: </span></b><span style="font-size:12.0pt;color:black">lustre-discuss <lustre-discuss-bounces@lists.lustre.org> on behalf of Jon Marshall via lustre-discuss <lustre-discuss@lists.lustre.org><br>
<b>Reply-To: </b>Jon Marshall <Jon.Marshall@cruk.cam.ac.uk><br>
<b>Date: </b>Friday, July 21, 2023 at 5:35 AM<br>
<b>To: </b>"lustre-discuss@lists.lustre.org" <lustre-discuss@lists.lustre.org><br>
<b>Subject: </b>[EXTERNAL] [BULK] [lustre-discuss] ldiskfs patch rejected Rocky 8.6<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">Hi,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">Me again! I now have a successful build of lustre server with ZFS support, thanks all for your help with this. I'm now stuck on getting ldiskfs support to work - specifically it requires the kernel-debuginfo
and debugsource packages, which on Rocky 8.6, don't exist for the kernel I'm building against (4.18.0-372.9.1.el8.x86_64). I've installed the only ones that exist, for kernel 4.18.0-477.15.1.el8_8 and hackily symlinked it to the current kernel to get lustre
to build against it, which it does, but then it fails on applying patches, which I suppose is not surprising. I assumed that having the e2fsprogs devel installed would do the trick but the build is specific in looking in /usr/src/kernel and /usr/src/debug/kernel,
neither of which have it.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">I'd like ldiskfs support as we currently run this fs on the MDT. However, we're only doing that because when we put the filesystem in place (which was a while ago) I'd read a fair amount warning
against using ZFS on MDT due to potential performance issues. I've had a trawl through the mailing list and I can't see anyone having issues with newer ZFS versions so I guess my question is, is this still a thing? I've been planning to move to ZFS at some
point anyway and it seems like this would be a good opportunity to do so but I thought I'd check and see if anyone had any advice.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">Thanks in advance<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">Jon<o:p></o:p></span></p>
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<p><span style="color:#595959">Jon Marshall</span><span style="color:black"><o:p></o:p></span></p>
<p><span style="font-size:10.0pt;color:#595959">High Performance Computing Specialist</span><span style="color:black"><o:p></o:p></span></p>
<p><span style="font-size:10.0pt;color:#595959"> </span><span style="color:black"><o:p></o:p></span></p>
<p><b><span style="color:#595959">IT and Scientific Computing Team</span></b><span style="color:black"><o:p></o:p></span></p>
<p><span style="font-size:10.0pt;color:#595959"> </span><span style="color:black"><o:p></o:p></span></p>
<p><span style="font-size:10.0pt;color:#595959">Cancer Research UK Cambridge Institute</span><span style="color:black"><o:p></o:p></span></p>
<p><span style="font-size:10.0pt;color:#595959">Li Ka Shing Centre | Robinson Way | Cambridge | CB2 0RE</span><span style="color:black"><o:p></o:p></span></p>
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