FreeBSD ZFS file server with SSD HDD

Kate Dawson k4t at 3msg.es
Thu Oct 12 10:38:22 UTC 2017


On Wed, Oct 11, 2017 at 09:41:13AM -0500, Adam Vande More wrote:
> On Wed, Oct 11, 2017 at 8:05 AM, Kate Dawson <k4t at 3msg.es> wrote:
> 
> > Hi,
> >
> > If I look at the output of `zpool iostat -v tank 1 ` I see that every
> > five seconds or so, the numner of write operation go to > 2k
> >
> > I think this shows that the I'm hitting the limit that the spinning disk
> > can provide in this workload.
> >
> 
> I doubt that is the cause.  It is more likely you have
> 
> vfs.zfs.txg.timeout

This is set to 5 


I may try decreasing it and seeing how things go for a few hours.

> 
> set to the default.  Have you tried any other zfs or nfs tuning?  If so,
> please share those details.


vfs.zfs.l2arc_noprefetch=0

zfs get sync tank/exports/xendomu
NAME                  PROPERTY  VALUE     SOURCE
tank/exports/xendomu  sync      disabled  local


> 
> Does gstat reveal anything useful?
> 

Thanks for this tool... on regular occasions drives show high percentage busy


dT: 1.001s  w: 1.000s  filter: eli                                                                                                                                               L(q)  ops/s    r/s   kBps   ms/r    w/s   kBps   ms/w   %busy Name

    5    247      0      0    0.0    247  15160   16.2   69.1| da2.eli                
    0    304      0      0    0.0    304  16219   14.1   71.6| da3.eli
    0    240      0      0    0.0    240  15108   16.3   66.6| da4.eli
    2    231      0      0    0.0    231  16695   16.1   65.0| da5.eli
    1    227      0      0    0.0    227  16703   16.5   66.7| da9.eli
    0    304      0      0    0.0    304  16219   13.8   72.7| da8.eli
    0    193      0      0    0.0    193  15872   20.2   65.8| ada0.eli
    3    263      0      0    0.0    263  13878   15.7   70.7| ada2.eli
    0    193      0      0    0.0    193  15872   20.4   64.6| ada1.eli
    3    269      0      0    0.0    269  13914   14.7   69.9| ada3.eli
    0    256      0      0    0.0    256  16139   16.4   71.5| ada4.eli
    0    258      0      0    0.0    258  16139   16.6   72.5| ada5.eli



dT: 1.001s  w: 1.000s  filter: eli
 L(q)  ops/s    r/s   kBps   ms/r    w/s   kBps   ms/w   %busy Name
    0    265      6    739   36.8    257  19425   17.5  103.0| da2.eli
    0    260      1    108   18.0    258  21643   25.8   87.1| da3.eli
    0    268      8    927   29.4    258  19437   20.2   95.0| da4.eli
    1    305     14   1754   32.6    289  21379   17.6  101.2| da5.eli
    0    300      8    871   34.8    290  21391   20.1   98.4| da9.eli
    0    273     15   1786   30.2    257  21635   19.7   94.1| da8.eli
    0    292     13   1378   29.5    278  21731   22.9  103.0| ada0.eli
    0    285     10   1187   30.2    273  21003   16.5   77.7| ada2.eli
    0    290     10   1091   40.0    279  21731   20.6   97.7| ada1.eli
    0    269      4    384   33.4    263  21015   19.7  112.2| ada3.eli
    0    251      5    619   23.0    245  21343   21.4   89.0| ada4.eli
    0    250      7    791   31.7    242  21199   21.7   88.3| ada5.eli


Here is some 30s or so of `zpool iostat tank 1 `


root at blue:/tank/exports/xendomu/restore # zpool iostat tank 1
               capacity     operations    bandwidth
pool        alloc   free   read  write   read  write
----------  -----  -----  -----  -----  -----  -----
tank        3.39T  2.05T     80    521  7.04M  13.8M
tank        3.39T  2.05T      2      0   160K      0
tank        3.39T  2.05T      8  1.74K   461K  45.4M
tank        3.39T  2.05T    107  1.04K  11.9M  25.0M
tank        3.39T  2.05T     29      0  2.48M      0
tank        3.39T  2.05T     27      0  1.38M      0
tank        3.39T  2.05T      4      0   116K      0
tank        3.39T  2.05T     15  1.52K  1.27M  23.4M
tank        3.39T  2.05T     12      0   846K      0
tank        3.39T  2.05T    901      0   108M      0
tank        3.39T  2.05T     14      0   814K      0
tank        3.39T  2.05T      1  1.34K  95.8K   103M
tank        3.39T  2.05T    249  1.90K  29.2M   114M
tank        3.39T  2.05T    530      0  59.4M      0
tank        3.39T  2.05T      3      0   180K      0
tank        3.39T  2.05T     83      0  7.47M      0
tank        3.39T  2.05T      4  2.80K   355K   106M
tank        3.39T  2.05T      5    229   263K  3.09M
tank        3.39T  2.05T      2      0   116K      0
tank        3.39T  2.05T      4      0   180K      0
tank        3.39T  2.05T      7      0   439K      0
tank        3.39T  2.05T      5  1.46K   447K  24.0M
tank        3.39T  2.05T      1      0  43.9K      0
tank        3.39T  2.05T    106      0  11.7M      0
tank        3.39T  2.05T     15      0   814K      0
tank        3.39T  2.05T     12      0   974K      0
tank        3.39T  2.05T     10  1.74K   675K  29.7M
tank        3.39T  2.05T      6      0   236K      0
tank        3.39T  2.05T     37      0  1.67M      0
tank        3.39T  2.05T      7      0   747K      0
tank        3.39T  2.05T      2      0  67.9K      0
tank        3.39T  2.05T      0  2.58K      0  90.9M
tank        3.39T  2.05T     19  1.38K  1.49M  20.6M
tank        3.39T  2.05T      1      0   140K      0
tank        3.39T  2.05T      0      0  43.9K      0
tank        3.39T  2.05T      3      0   164K      0
tank        3.39T  2.05T     61  3.36K  3.55M  78.4M

regards, 

Kate Dawson


-- 
"The introduction of a coordinate system to geometry is an act of violence"
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