Optimization of rclone mount for azureblob read-only random-seek of large files

What is the problem you are having with rclone?

I am using rclone to mount azureblob storage. Of course that works fine.

The “issue” is that I need to try to better optimize the configuration for read-only and random-seek access of large “files” / object (each blob in azure is 0.5 gb to 2.0 gb).

Additionally, I would like to understand better if setting up a large “RAMdisk” of roughly 16-32 GB would be help for the vfs cache or not?

The VM that is using rclone is in the same data center as the azure storage account to optimize network connectivity.

Run the command 'rclone version' and share the full output of the command.

Which cloud storage system are you using? (eg Google Drive)

Azure

The command you were trying to run (eg rclone copy /tmp remote:tmp)

rclone mount (this is "working" I am just trying to optimize for my us case)

Please run 'rclone config redacted' and share the full output. If you get command not found, please make sure to update rclone.

PS C:\Users\sc-abaras1\Downloads\rclone-v1.72.1-windows-amd64\rclone-v1.72.1-windows-amd64> .\rclone config redacted
[adls-share]
type = azureblob
account = XXX
key = XXX
vfs_cache_mode = minimal
vfs_read_chunk_size = 512K
vfs_read_chunk_size_limit = 4M
vfs_read_ahead = 1M
buffer_size = 1M
multi_thread_streams = 4
transfers = 8
checkers = 8
low_level_retries = 10
timeout = 5m
contimeout = 30s
dir_cache_time = 30m
attr_timeout = 30m
no_modtime = true
no_checksum = true
vfs_fast_fingerprint = true
links = true

A log from the command that you were trying to run with the -vv flag

PS C:\Users\sc-abaras1\Downloads\rclone-v1.72.1-windows-amd64\rclone-v1.72.1-windows-amd64> .\rclone.exe mount adls-share:halo-poc-object-store C:\AzureADLS --config .\adls-share.conf -vv
2025/12/18 12:43:48 DEBUG : rclone: Version "v1.72.1" starting with parameters ["C:\\Users\\sc-abaras1\\Downloads\\rclone-v1.72.1-windows-amd64\\rclone-v1.72.1-windows-amd64\\rclone.exe" "mount" "adls-share:halo-poc-object-store" "C:\\AzureADLS" "--config" ".\\adls-share.conf" "-vv"]
2025/12/18 12:43:48 DEBUG : Creating backend with remote "adls-share:halo-poc-object-store"
2025/12/18 12:43:48 DEBUG : Using config file from "C:\\Users\\sc-abaras1\\Downloads\\rclone-v1.72.1-windows-amd64\\rclone-v1.72.1-windows-amd64\\adls-share.conf"
2025/12/18 12:43:48 INFO  : Azure container halo-poc-object-store: poll-interval is not supported by this remote
2025/12/18 12:43:48 DEBUG : Network mode mounting is disabled
2025/12/18 12:43:48 DEBUG : Mounting on "C:\\AzureADLS" ("adls-share halo-poc-object-store")
2025/12/18 12:43:48 DEBUG : Azure container halo-poc-object-store: Mounting with options: ["-o" "attr_timeout=1" "-o" "uid=-1" "-o" "gid=-1" "--FileSystemName=rclone" "-o" "volname=adls-share halo-poc-object-store"]
2025/12/18 12:43:48 DEBUG : Azure container halo-poc-object-store: Init:
2025/12/18 12:43:48 DEBUG : Azure container halo-poc-object-store: >Init:
2025/12/18 12:43:48 DEBUG : /: Statfs:
2025/12/18 12:43:48 DEBUG : /: >Statfs: stat={Bsize:4096 Frsize:4096 Blocks:274877906944 Bfree:274877906944 Bavail:274877906944 Files:1000000000 Ffree:1000000000 Favail:0 Fsid:0 Flag:0 Namemax:255}, errc=0
2025/12/18 12:43:48 DEBUG : /: Getattr: fh=0xFFFFFFFFFFFFFFFF
2025/12/18 12:43:48 DEBUG : /: >Getattr: errc=0
2025/12/18 12:43:48 DEBUG : /: Readlink:
2025/12/18 12:43:48 ERROR : symlinks not supported without the --links flag: /
2025/12/18 12:43:48 DEBUG : /: >Readlink: errc=-40, linkPath=""
2025/12/18 12:43:48 DEBUG : /: Getxattr: name="non-existant-a11ec902d22f4ec49003af15282d3b00"
2025/12/18 12:43:48 DEBUG : /: >Getxattr: errc=-40, value=""
The service rclone has been started.
2025/12/18 12:43:48 DEBUG : /: Getattr: fh=0xFFFFFFFFFFFFFFFF
2025/12/18 12:43:48 DEBUG : /: >Getattr: errc=0
2025/12/18 12:43:48 DEBUG : /: Getattr: fh=0xFFFFFFFFFFFFFFFF
2025/12/18 12:43:48 DEBUG : /: >Getattr: errc=0
2025/12/18 12:43:48 DEBUG : /: Opendir:
2025/12/18 12:43:48 DEBUG : /: OpenFile: flags=O_RDONLY, perm=-rwxrwxrwx
2025/12/18 12:43:48 DEBUG : /: >OpenFile: fd=/ (r), err=<nil>
2025/12/18 12:43:48 DEBUG : /: >Opendir: errc=0, fh=0x0
2025/12/18 12:43:48 DEBUG : /: Releasedir: fh=0x0
2025/12/18 12:43:48 DEBUG : /: >Releasedir: errc=0
The service rclone has been stopped.
2025/12/18 12:44:05 DEBUG : Azure container halo-poc-object-store: Destroy:
2025/12/18 12:44:05 DEBUG : Azure container halo-poc-object-store: >Destroy:
2025/12/18 12:44:05 DEBUG : Not calling host.Unmount as mount already Destroyed
2025/12/18 12:44:05 DEBUG : Unmounted successfully
2025/12/18 12:44:05 NOTICE: C:\AzureADLS: Unmounted rclone mount
2025/12/18 12:44:05 DEBUG : rclone: Version "v1.72.1" finishing with parameters ["C:\\Users\\sc-abaras1\\Downloads\\rclone-v1.72.1-windows-amd64\\rclone-v1.72.1-windows-amd64\\rclone.exe" "mount" "adls-share:halo-poc-object-store" "C:\\AzureADLS" "--config" ".\\adls-share.conf" "-vv"]

welcome to the forum,

about your config, most of the values do not belong in the config file.
for example, vfs_cache_mode = minimal does nothing, remove that and add it to the command itself.
if you had been using the vfs file cache, you would see an entry like this in the your debug log

DEBUG : Encrypted drive 'remote': vfs cache: root is "d:\\rclone\\cache\\remote"

checkers = 8 does nothing on a mount, so remove it.

no_checksum = true is not valid in config file
no_modtime = true is not valid in config file
and that applies to many other flags that do not belong in the config file.


afiak, in that case, rclone is not caching the reads at all.
i think you need vfs_cache_mode = full

also, if you plan to read-only from the remote, safer to use --read-only


fwiw, i have a summary of two vfs caches

This is actually how are run

.\rclone mount adls-share:halo-poc-object-store C:\Users\haloaccess\adls-share --config .\adls-share.conf
--read-only --links
--vfs-cache-mode full --vfs-cache-max-size 2G
--vfs-cache-poll-interval 15s --vfs-cache-max-age 24h
--vfs-read-chunk-size 32M --vfs-read-chunk-streams 4
--vfs-read-chunk-size-limit 256M --vfs-read-ahead 512M
--dir-cache-time 5m --buffer-size 64M
--transfers 8 --checkers 16
--timeout 60s --contimeout 10s
--low-level-retries 3 --retries 3
--cache-dir C:\temp\rclone-cache

with adls-share.conf contain

[adls-share]
type = azureblob
account = haloapblobfuse2smb
key = [key]

Any thoughts on this

please post the top thirty lines of the debug output, so we can see the the real command and all flags.
and make sure to enclose that text with three backticks for readability.
https://itsfoss.com/markdown-code-block/


as mentioned, does nothing on mount, so remove that.

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