[shard 107] seastar - Could not setup Async I/O: Resource temporarily unavailable. The most common cause is not enough request capacity in /proc/sys/fs/aio-max-nr. Try increasing that number or reducing the amount of logical CPUs available for your a

[Praveen Kumar]

Hi,

I am trying to run scylla_setup and getting below  error.

Using 38  hyperthreads and Ubuntu 20.4. Trying to install scylla 4.3.

Yes - runs a script to verify that the kernel for this instance qualifies to run Scylla. No - skips the kernel check.

[YES/no]yes

ERROR 2021-02-05 04:20:16,796 [shard 107] seastar - Could not setup Async I/O: Resource temporarily unavailable. The most common cause is not enough request capacity in /proc/sys/fs/aio-max-nr. Try increasing that number or reducing the amount of logical CPUs available for your application

ERROR 2021-02-05 04:20:16,797 [shard 105] seastar - Could not setup Async I/O: Resource temporarily unavailable. The most common cause is not enough request capacity in /proc/sys/fs/aio-max-nr. Try increasing that number or reducing the amount of logical CPUs available for your application

ERROR 2021-02-05 04:20:16,796 [shard 106] seastar - Could not setup Async I/O: Resource temporarily unavailable. The most common cause is not enough request capacity in /proc/sys/fs/aio-max-nr. Try increasing that number or reducing the amount of logical CPUs available for your application

Please upgrade to a newer kernel version.

see https://docs.scylladb.com/troubleshooting/error_messages/kb_fs_not_qualified_aio/ for details

[Avi Kivity]

What's the value of /proc/sys/fs/aio-max-nr?

What kernel version are you using?

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[Benny Halevy]

On Thu, 2021-02-04 at 14:12 -0800, Praveen Kumar wrote:
> Hi,
> I am trying to run scylla_setup and getting below  error.
> Using 38  hyperthreads and Ubuntu 20.4. Trying to install scylla 4.3.
>

what is the the value of /proc/sys/fs/aio-max-nr ?

The default value (65536) is insufficient.
Scylla (seastar actually) currently requires around 11K aio slots per cpu
so with 38 hyperthreads you'll need to set aio-max-nr to above 430000.
I recommend setting it to 524288 to be on the safe side.

To change that in a persistent manner you can set
fs.aio-max-nr = 524288
in /etc/sysctl.conf or in a file under /etc/sysctl.d

> Yes - runs a script to verify that the kernel for this instance qualifies to run Scylla. No - skips the kernel check.
> [YES/no]yes
> ERROR 2021-02-05 04:20:16,796 [shard 107] seastar - Could not setup Async I/O: Resource temporarily unavailable. The most common cause is not enough
> request capacity in /proc/sys/fs/aio-max-nr. Try increasing that number or reducing the amount of logical CPUs available for your application
> ERROR 2021-02-05 04:20:16,797 [shard 105] seastar - Could not setup Async I/O: Resource temporarily unavailable. The most common cause is not enough
> request capacity in /proc/sys/fs/aio-max-nr. Try increasing that number or reducing the amount of logical CPUs available for your application
> ERROR 2021-02-05 04:20:16,796 [shard 106] seastar - Could not setup Async I/O: Resource temporarily unavailable. The most common cause is not enough
> request capacity in /proc/sys/fs/aio-max-nr. Try increasing that number or reducing the amount of logical CPUs available for your application
> Please upgrade to a newer kernel version.
>  see https://docs.scylladb.com/troubleshooting/error_messages/kb_fs_not_qualified_aio/ for details

[Ivan Prisyazhnyy]

The question was answered on the users slack by Lubos with the link to https://github.com/scylladb/scylla/pull/7252/files

To view this discussion on the web visit https://groups.google.com/d/msgid/scylladb-users/ca31c44212087024913f7f387a3a3e63ec082d16.camel%40scylladb.com.