current maximum stripe unit size?

current maximum stripe unit size?

[Ede Wolf]

Hello,

having found different values, as of Kernel 5.10, what is the maximum 
allowed size in K for stripe units?

I came across limits from 64k - 256k, but the documentation  always 
seemed quite aged.

Thanks

Ede

Re: current maximum stripe unit size?

[Eric Sandeen]

On 4/29/21 9:10 AM, Ede Wolf wrote:
> Hello,
> 
> having found different values, as of Kernel 5.10, what is the maximum allowed size in K for stripe units?
> 
> I came across limits from 64k - 256k

Where did you read that?

> , but the documentation  always seemed quite aged.

Current mkfs limits are UINT_MAX for stripe unit and stripe width (so width is the effective limiter in most cases)

Interestingly, in the kernel the limit on swidth is INT_MAX. In any case, quite large.

(However, the /log/ stripe unit has a limit of 256; if the data stripe unit is larger, the log stripe unit will automatically be reduced.)

-Eric

> Thanks

Re: current maximum stripe unit size?

[Ede Wolf]

Hello,

thanks for replying. Indeed I did not distinguish between log and data 
stripe set - as I did not know, those can be treated independendly.

The docs I have all talking about log stripe size, I was just under the 
impression, those set the overall limit.

Thanks again

Ede

Am 03.05.21 um 15:22 schrieb Eric Sandeen:
> 
> 
> On 4/29/21 9:10 AM, Ede Wolf wrote:
>> Hello,
>>
>> having found different values, as of Kernel 5.10, what is the maximum allowed size in K for stripe units?
>>
>> I came across limits from 64k - 256k
> 
> Where did you read that?
> 
>> , but the documentation  always seemed quite aged.
> 
> Current mkfs limits are UINT_MAX for stripe unit and stripe width (so width is the effective limiter in most cases)
> 
> Interestingly, in the kernel the limit on swidth is INT_MAX. In any case, quite large.
> 
> (However, the /log/ stripe unit has a limit of 256; if the data stripe unit is larger, the log stripe unit will automatically be reduced.)
> 
> -Eric
> 
>> Thanks
>