[lustre-discuss] Unexpected result with overstriping

[Nathan Dauchy]

John,

I believe the lfs-setstripe man page is incorrect (or at least misleading) in this case. I recall seeing 2000 hardcoded as a maximum, so it appears to be picking that.

Using "-C -1" to put a single stripe on each OST wouldn't have any benefit over "-c -1".   IMHO, it would probably be more useful to have negative values represent number of stripes per OST. 🙂

-Nathan
________________________________
From: lustre-discuss <lustre-discuss-bounces at lists.lustre.org> on behalf of John Bauer <bauerj at iodoctors.com>
Sent: Friday, May 17, 2024 8:48 AM
To: lustre-discuss <lustre-discuss at lists.lustre.org>
Subject: [lustre-discuss] Unexpected result with overstriping

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Good morning all,

I am playing around with overstriping a bit and I found a behavior that, to me, would seem unexpected.  The documentation for -C -1  indicates that the file should be striped over all available OSTs.  The pool, which happens to be the default, is ssd-pool which has 32 OSTs.  I got a stripeCount of 2000.  Is this as expected?

pfe20.jbauer2 213> rm -f /nobackup/jbauer2/ddd.dat
pfe20.jbauer2 214> lfs setstripe -C -1 /nobackup/jbauer2/ddd.dat
pfe20.jbauer2 215> lfs getstripe /nobackup/jbauer2/ddd.dat
/nobackup/jbauer2/ddd.dat
lmm_stripe_count:  2000
lmm_stripe_size:   1048576
lmm_pattern:       raid0,overstriped
lmm_layout_gen:    0
lmm_stripe_offset: 119
lmm_pool:          ssd-pool
    obdidx         objid         objid         group
       119          52386287        0x31f59ef                 0
       123          52347947        0x31ec42b                 0
       127          52734487        0x324aa17                 0
       121          52839396        0x32643e4                 0
       131          52742709        0x324ca35                 0
       116          52242659        0x31d28e3                 0
       117          51831125        0x316e155                 0
       124          52425218        0x31ff202                 0
       125          52402722        0x31f9a22                 0
       106          52700581        0x32425a5                 0

edited for brevity

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