Re: Disappointing speed with ZFS

`--# dd if=/dev/zero of=test.tmp bs=1024k count=10000
load: 0.42  cmd: dd 30773 [zfs:(&tx->tx_quiesce_done_cv)] 0.01u 3.56s  
5% 1996k
2612+0 records in
2611+0 records out
2737831936 bytes transferred in 65.497687 secs (41800437 bytes/sec)
10000+0 records in
10000+0 records out
10485760000 bytes transferred in 211.643188 secs (49544519 bytes/sec)



`--# dd if=test.tmp of=test2.tmp

(AD6 is my device)

       tty             ad4              ad5               
ad6             cpu
  tin tout  KB/t tps  MB/s   KB/t tps  MB/s   KB/t tps  MB/s  us ni sy  
in id
    1  238  0.00   0  0.00  60.22  18  1.04  64.00 982 61.37   1  0  
31  2 67
    1 3349  0.00   0  0.00  64.00   7  0.43  58.53 757 43.26   1  0  
46  0 53
    0  286  0.00   0  0.00  55.81  21  1.13  64.00 487 30.43   1  0  
31  1 67
    0  269  0.00   0  0.00  64.00   8  0.50  64.00  21  1.31   2  0  
49  0 49
    0  294  0.00   0  0.00  32.82  34  1.09  63.16 582 35.92   1  0  
49  2 48
    0  278  0.00   0  0.00  60.00  15  0.86  64.00 983 61.45   0  0  
23  0 77
    0  280  0.00   0  0.00  56.00  15  0.80  63.64 959 59.60   0  0  
23  2 75
    0  297  0.00   0  0.00  62.55  11  0.67  47.94 197  9.21   1  0  
55  0 44
    0  268  0.00   0  0.00  53.80  20  1.05  64.00 481 30.03   1  0  
52  0 48
    0  290  0.00   0  0.00  57.71  14  0.79  63.23 597 36.89   1  0  
54  0 45
    0  289  0.00   0  0.00  53.82  11  0.57  64.00 982 61.39   0  0  
27  1 71
    0  276  0.00   0  0.00  57.18  17  0.94  63.32 963 59.56   0  0  
43  1 55
    0  296  0.00   0  0.00  61.33  18  1.06  64.00 983 61.44   1  0  
37  1 61
    0  280  0.00   0  0.00  61.60  14  0.87  63.83 927 57.79   0  0   
3  2 94
    0  306 16.00   1  0.02  57.82  11  0.62  59.20 486 28.10   1  0  
46  0 53
    0  251  0.00   0  0.00  62.77  13  0.79  63.17 933 57.57   1  0  
35  3 61
    0  295  0.00   0  0.00  53.25  16  0.83  42.87 133  5.56   1  0  
51  0 48
    0  293  0.00   0  0.00  58.00  10  0.57  64.00 501 31.34   2  0  
49  0 49
    0  265  0.00   0  0.00  38.55  11  0.41  64.00 505 31.57   1  0  
33  1 65
    0  299  0.00   0  0.00  54.67  18  0.96  62.65  76  4.65   0  0  
53  0 47



On 11.02.2008, at 20:21, Ivan Voras wrote:

> On 11/02/2008, Alexey Tarasov <me_at_lexasoft.ru> wrote:
>> I've done similar tests on the other machine, and all looks fine.
>>
>> But why on this machine ZFS works slower than UFS? When I make UFS
>> file system on the same disk, rtorrent hashing works 10 times faster.
>> And while hashing, HDD is used three times intensively with ZFS
>> (noticed by flashing LED).
>>
>> I have an amd64 Core2Duo processor, 4 Gb of RAM, what is not enough
>> for ZFS?
>>
>> What kernel tuning can help me?
>
> Ok, so you're saying that you've done similar testing (meaning
> rtorrent hashing) on other machines, and they work fine, but only this
> one is slow?
>
> There's no usual reason why would it be so.
>
> Can you try the suggestion I made (dd+iostat)?

--
Alexey Tarasov

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