Re: WAPL panic

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

> This looks wrong.
Remember I was only testing read performance then.

> The 6.0 kernel will never, under any circumstances, issue a transfer larger 
> than 64K to a disk device, not even a pseudodevice like RAIDframe
I'm well aware of that.
That's why now, I'm testing write performance.

> What fragment size are you using?
The default, whatever that is.


I can repeat the results of my read tests so you don't have to dig for them:
Column titles are fsbsize/SPSU, all on a five-component Level 5 RAID.

Extraction (minutes):
        16k/32  16k/8   16k/128 32k/128 64k/128 64k/32
home    163      81*    151     326**   116     79
mail    146     113*    137     525**   109     94
*without quota (by mistake)
**without WAPL (by mistake)

In the following, + means atime, - noatime.

find (seconds):
        16k/32  16k/8   16k/128 32k/128 64k/128 64k/32
home+   158     178     167     128      98     103
home-    79      86      76      77      73      76
mail+    82     ???      81      59      47      52
mail-    56      59      54      44      39      41
???: forgot to measure

tar (seconds):
        16k/32  16k/8   16k/128 32k/128 64k/128 64k/32
home+   577     639     536     476     406     418
home-   422     466     369     401     362     361
mail+   600     690     587     450     371     395
mail-   411     484     375     348     318     337

parallel tars (seconds):
        16k/32  16k/8   16k/128 32k/128 64k/128 64k/32
home+   430+506 497+574 389+466 379+450 269+327 332+358
home-   302+360 355+412 275+333 319+380 242+290 294+288
mail+   431+444 496+505 419+431 343+350 252+254 285+288
mail-   246+255 289+290 234+237 245+254 203+204 231+233


The last test (parallel tars) was meant to, in addition to the backup 
simulation the other two tests did, simulate concurrent access by users.