LLAPI_PCC_DEL(3)

💅 LLAPI_PCC_DEL — bestie edition 💅

okay so this is a page from the lustre library functions manual set (section 3, the library-call girlies ✨). it's basically the "bye bye PCC backend" button and i'm obsessed with it, let's get into it 🫶

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✨ NAME ✨

llapi_pcc_del — Delete a PCC backend from a client 🌸

no cap, that's the whole job description: it deletes a PCC backend off a client. that's it, that's the vibe.

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✨ SYNOPSIS ✨

#include <lustre/lustreapi.h>

int llapi_pcc_del(const char *mntpath, const char *pccpath,
                  enum lu_pcc_cleanup_flags flags);

three args, one include, zero drama 💖

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✨ DESCRIPTION ✨

so like, llapi_pcc_del() deletes a PCC backend that's referenced by pccpath, on the client whose mount point is mntpath. iconic. main character behavior fr fr.

by default, when you remove a PCC backend from a client, the move is to scan the PCC backend fs, and then uncache — meaning detach and remove — all the scanned PCC copies from PCC by FIDs. so yeah, it goes through and yanks every copy it finds, identified by FID. very thorough, very "blocked and deleted" energy 💅

now, the input parameter flags currently only has one value, and it's PCC_CLEANUP_FL_KEEP_DATA. what that means is: it removes the PCC backend from the Lustre client but retains the data on the cache. bestie, that is the "we can still be friends" option 🥺 in this case the PCC-RW backend falls back to being a traditional HSM storage solution, and the file data is still accessible — as long as the copytool is still running on this client. so like, the copytool has to stay up, okay? don't close the app 😭

⚠️ heads up: that "data still accessible" thing is conditional. copytool running on this client = fine. copytool not running = not fine. no guessing, that's literally what the manpage says, i'm just making sure you saw it 👀

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✨ RETURN VALUES ✨

• 0 — success, slay, we ate ✨
• negative errno value — failure, it's giving sad girl hours 😭

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✨ ERRORS ✨

• -ENOMEM — Insufficient memory to complete operation. she's out of brain space 🧠💀
• -EFAULT — Memory region is not properly mapped. the memory is... not where it said it would be 🙈
• -EINVAL — One or more invalid arguments are given. bestie we talked about this, check your args 💅
• -EOPNOTSUPP — PCC backend operation is not supported. this operation said "not today" 💀

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✨ AVAILABILITY ✨

llapi_pcc_del() is part of the lustre(7) user application interface library, and it's been around since release 2.16.0. so like, if you're on something older than that... no she's not there yet, sorry 🎀

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✨ SEE ALSO ✨

• lustreapi(7) 🦋

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and that's the whole page!! ty for reading my little unix info dump, mwah 💖 writing this out was a Lustre User API moment, dated 2024-08-28 in the archives of my heart. bye bestie, go delete responsibly 🎀✨👑