[LUDOC-49] MDT calculations don't include striping adjustments (Ch 5) Created: 19/Mar/12  Updated: 26/Aug/13  Resolved: 26/Aug/13

Status: Resolved
Project: Lustre Documentation
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Improvement Priority: Minor
Reporter: Richard Henwood (Inactive) Assignee: Richard Henwood (Inactive)
Resolution: Fixed Votes: 0
Labels: QContent

Issue Links:
Related
is related to LUDOC-102 Put descriptions of "Inode size" and ... Resolved
Business Value: 18
Rank (Obsolete): 7163

 Description   

The size of the MDT you need is proportional to the number of files you want to store and the number of stripes you anticipate using. Strips are not mentioned in the Manual in the section on calculating MTS size.

https://build.whamcloud.com/job/lustre-manual/lastSuccessfulBuild/artifact/lustre_manual.html#dbdoclet.50438256_87676

Cliff describes the situation thus:

[3:00:02 PM CDT] Richard Henwood: What is an approximate maximum number of files that I can have if my MDT is 450GB? The Manual says 2KB/inode which gives: 225 000 000. Does that sounds about right?
[3:19:46 PM CDT] Cliff White: inode size depends on stripe count. If no striping, afaik could be 512bytes/inode
[3:20:15 PM CDT] Cliff White: 2kb is somewhere arount 80 stripes, i think, ~4.5K is 160 stripes


 Comments   
Comment by Jodi Levi (Inactive) [ 19/Mar/13 ]

Richard to get more information on this request.

Comment by Linda Bebernes (Inactive) [ 01/Jul/13 ]

Removed obsolete note from section 5.2.1:
Inode size depends on stripe count. Without any stripes an inode allocation of 512 bytes might be sufficient. As striping grows to ~80 stripes per file, the inode allocation is around 2KB. At 160 stripes, a rough estimate for inode allocation is 4.5KB

Comment by Linda Bebernes (Inactive) [ 01/Jul/13 ]

Changes are ready for review at http://review.whamcloud.com/#/c/6847/

Comment by Linda Bebernes (Inactive) [ 26/Aug/13 ]

Changes merged

Generated at Sat Feb 10 03:39:50 UTC 2024 using Jira 9.4.14#940014-sha1:734e6822bbf0d45eff9af51f82432957f73aa32c.