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These numbers are just estimates, you can use values more suitable to your workload.
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<div class="">Similarly, 32-core clients may be on the low side these days. NVIDIA DGX nodes have 256 cores, though you may not have 1024 of them.
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<div class="">The net answer is that having 64GB+ of RAM is inexpensive these days and improves MDS performance, especially if you compare it to the cost of client nodes that would sit waiting for filesystem access if the MDS is short of RAM. Better to have
too much RAM on the MDS than too little.</div>
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<div class="">Cheers, Andreas <br class="">
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<div class="">On Mar 4, 2024, at 00:56, Amin Brick Mover via lustre-discuss <<a href="mailto:lustre-discuss@lists.lustre.org" class="">lustre-discuss@lists.lustre.org</a>> wrote:</div>
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<div class="gmail_default" style="font-size:large"><span style="color:rgb(13,13,13);font-family:Söhne,ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Ubuntu,Cantarell,"Noto Sans",sans-serif,"Helvetica Neue",Arial,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol","Noto Color Emoji";font-size:16px" class="">In
the Lustre Manual 5.5.2.1 section, the examples mentioned:</span></div>
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<div class="gmail_default" style=""><i style="" class="">For example, for a single MDT on an MDS with 1,024 compute nodes, 12 interactive login nodes, and a</i></div>
<div class="gmail_default" style=""><i style="" class="">20 million file working set (of which 9 million files are cached on the clients at one time):</i></div>
<div class="gmail_default" style=""><i style="" class="">Operating system overhead = 4096 MB (RHEL8)</i></div>
<div class="gmail_default" style=""><i style="" class="">File system journal = 4096 MB</i></div>
<div class="gmail_default" style=""><i style="" class="">1024 * 32-core clients *
<font color="#ff0000" class="">256 files/core</font> * 2KB = 16384 MB</i></div>
<div class="gmail_default" style=""><i style="" class="">12 interactive clients *
<font color="#ff0000" class="">100,000 files</font> * 2KB = 2400 MB</i></div>
<div class="gmail_default" style=""><i style="" class="">20 million file working set * 1.5KB/file = 30720 MB</i></div>
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<div class="gmail_default" style="font-size:large"><span style="color:rgb(13,13,13);font-family:Söhne,ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Ubuntu,Cantarell,"Noto Sans",sans-serif,"Helvetica Neue",Arial,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol","Noto Color Emoji";font-size:16px" class="">I'm
curious, how were the two numbers, </span><span style="font-family:Söhne,ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Ubuntu,Cantarell,"Noto Sans",sans-serif,"Helvetica Neue",Arial,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol","Noto Color Emoji";font-size:16px" class=""><font color="#ff0000" class="">256
files/core</font></span><span style="color:rgb(13,13,13);font-family:Söhne,ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Ubuntu,Cantarell,"Noto Sans",sans-serif,"Helvetica Neue",Arial,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol","Noto Color Emoji";font-size:16px" class="">
and </span><span style="font-family:Söhne,ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Ubuntu,Cantarell,"Noto Sans",sans-serif,"Helvetica Neue",Arial,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol","Noto Color Emoji";font-size:16px" class=""><font color="#ff0000" class="">100,000
files</font></span><span style="color:rgb(13,13,13);font-family:Söhne,ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Ubuntu,Cantarell,"Noto Sans",sans-serif,"Helvetica Neue",Arial,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol","Noto Color Emoji";font-size:16px" class="">,
determined? Why?</span></div>
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<div>Cheers, Andreas</div>
<div>--</div>
<div>Andreas Dilger</div>
<div>Lustre Principal Architect</div>
<div>Whamcloud</div>
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