[DRBD-user] drbd storage size

Cesar Peschiera brain at click.com.py
Mon Oct 27 14:50:48 CET 2014

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Hi Ivan

Many thanks for the warnings

I know about of the tuning for the RAID controller, DRBD, but not of cpu 
pinning in KVM. I should see this topic.

If you have information for me about this topic, please let me know, i use 
proxmox as Virtualization System (based on KVM and Openvz)

Best regards
Cesar Peschiera


----- Original Message ----- 
From: "Ivan" <ivan at c3i.bg>
To: "Cesar Peschiera" <brain at click.com.py>
Sent: Saturday, October 25, 2014 10:53 AM
Subject: Re: [DRBD-user] drbd storage size


> Hi Cesar,
>
> On 10/25/2014 04:17 PM, Cesar Peschiera wrote:
>> Hi Ivan
>>
>> Thanks for the link, it seem very interesting. In my case, each server 
>> have
>> 2 Intel processors of 10 cores and 20 threads, according with this link:
>> http://ark.intel.com/products/75279/Intel-Xeon-Processor-E5-2690-v2-25M-Cache-3_00-GHz
>>
>>
>> But i have a question for do about of DRBD and MS-SQL Server 2008 x64, as 
>> i
>> use KVM for virtualize a Windows Server with MS-SQL Server, and i only 
>> have
>> this VM on the Server. What will be better for me in terms of 
>> performance,
>> enable or not the threads of the processors?
>
> you mean hyperthreading ? I can't really advice on that, but from what 
> I've read on forums it's OK to have it enabled (only the first versions of 
> cpus with hyperthreading many years ago had problems).
>
> You should also investigate cpu pinning in KVM.
>
> That said I don't think you'll be CPU bound if all you run is a database 
> server. The bottleneck will rather be I/O, so you'll have to understand 
> kvm's caching strategy to make good use of the hefty setup you have. If 
> your raid controllers have a battery backup unit (BBU) you should be safe 
> with cache=none.
>
> Also, you'll have to use virtio drivers in windows.
>
> Have a look at that, it should help you.
>
> https://www.ibm.com/developerworks/community/blogs/sagitech/entry/tuning_kvm_guest_for_performance?lang=en
>
> good luck
> ivan
>
>
>>
>> Please, if you can explain me, do it clearly for that i can understand 
>> you.
>>
>> Best regards
>> Cesar
>>
>>
>> ----- Original Message ----- From: "Ivan" <ivan at c3i.bg>
>> To: <drbd-user at lists.linbit.com>
>> Sent: Saturday, October 25, 2014 9:12 AM
>> Subject: Re: [DRBD-user] drbd storage size
>>
>>
>>> Hi,
>>>
>>> On 10/25/2014 02:38 PM, Cesar Peschiera wrote:
>>>> Hi Meji
>>>>
>>>> In three weeks i will have two Intel NIC X520-QDA1 of 40 Gb/s, 
>>>> according
>>>> to these link:
>>>> http://ark.intel.com/products/68672/Intel-Ethernet-Converged-Network-Adapter-X520-QDA1
>>>>
>>>>
>>>> http://www.intel.com/content/www/us/en/network-adapters/converged-network-adapters/ethernet-x520-qda1-brief.html
>>>>
>>>>
>>>
>>> At those speeds it would be interesting to test the upcoming 3.18 kernel
>>> with the bulk network transmission patch [1] ; that should save you a
>>> bunch of cpu cycles.
>>>
>>> [1] http://lwn.net/Articles/615238
>>>
>>> ivan
>>>
>>>
>>>>
>>>> In my Hardware setup also i have a RAID controller H710p of Dell (LSI
>>>> chipset with 1 MB of cache) and with two groups of 4 HDDs SAS 15K RPM,
>>>> each group is  configured in RAID 10, this setup is applied for each
>>>> Server (the HDDs for the OS are in other RAID), obviously i don't have
>>>> much storage compared to yours.
>>>>
>>>> In these Servers i will have running DRBD 8.4.5 version
>>>>
>>>> If you want to know the result of my tests, only let me know.
>>>>
>>>> Best regards
>>>> Cesar
>>>>
>>>> ----- Original Message ----- From: "Meij, Henk" <hmeij at wesleyan.edu>
>>>> To: <drbd-user at lists.linbit.com>
>>>> Sent: Thursday, October 23, 2014 5:10 PM
>>>> Subject: Re: [DRBD-user] drbd storage size
>>>>
>>>>
>>>>> a) it turns out the counter  (8847740/11287100)M goes down, not up,
>>>>> deh, never noticed
>>>>>
>>>>> b) ran plain  rsync across eth0 (public, with switches/routers) and
>>>>> eth1 (nic to nic)
>>>>> eth0 sent 585260755954 bytes  received 10367 bytes  116690412.98
>>>>> bytes/sec
>>>>> eth1 sent 585260755954 bytes  received 10367 bytes  122580535.41
>>>>> bytes/sec
>>>>> so my LSI raid card is behaving and DRBD is slowing the initialization
>>>>> down somehow.
>>>>> Found chapter 15 and will try some suggestions but ideas welcome.
>>>>>
>>>>> c) for grins
>>>>> version: 8.4.5 (api:1/proto:86-101)
>>>>> GIT-hash: 1d360bde0e095d495786eaeb2a1ac76888e4db96 build by
>>>>> mockbuild at Build64R6, 2014-08-17 19:26:04
>>>>> 0: cs:SyncTarget ro:Secondary/Secondary ds:Inconsistent/UpToDate C
>>>>> r-----
>>>>>    ns:0 nr:3601728 dw:3601408 dr:0 al:0 bm:0 lo:4 pe:11 ua:3 ap:0 ep:1
>>>>> wo:f oos:109374215324
>>>>>        [>....................] sync'ed:  0.1% (106810756/106814272)M
>>>>>        finish: 731:23:05 speed: 41,532 (31,868) want: 41,000 K/sec
>>>>>
>>>>> 100TB in 731 hours would  be 30 days. Can I expect large delta data
>>>>> replication to go equally slow using DRDB?
>>>>>
>>>>> -Henk
>>>>>
>>>>>
>>>>>
>>>>> ________________________________________
>>>>> From: drbd-user-bounces at lists.linbit.com
>>>>> [drbd-user-bounces at lists.linbit.com] on behalf of Meij, Henk
>>>>> [hmeij at wesleyan.edu]
>>>>> Sent: Thursday, October 23, 2014 9:57 AM
>>>>> To: Philipp Reisner; drbd-user at lists.linbit.com
>>>>> Subject: Re: [DRBD-user] drbd storage size
>>>>>
>>>>> Thanks for the write up y'll.  I'll have to think about #3 not sure I
>>>>> grasp it fully.
>>>>>
>>>>> Last night I started a 12 TB test and started first initialization for
>>>>> observation (0 is primary).
>>>>> I have node0:eth1 wired directly into node1:eth1 with 10 foot CAT 6
>>>>> cable (MTU=9000)
>>>>> Data from node1 to node0
>>>>> PING 10.10.52.232 (10.10.52.232) 8970(8998) bytes of data.
>>>>> 8978 bytes from 10.10.52.232: icmp_seq=1 ttl=64 time=0.316 ms
>>>>>
>>>>> This morning's progress report from node1:(drbd v8.4.5)
>>>>>
>>>>>        [===>................] sync'ed: 21.7% (8847740/11287100)M
>>>>>        finish: 62:50:50 speed: 40,032 (39,008) want: 68,840 K/sec
>>>>>
>>>>> which confuses me: 8.8M out of 11.3M is 77.8% synced, not? I will let
>>>>> this test finish before I do a dd attempt.
>>>>>
>>>>> iostat reveals %idle cpu 99%+ and little to no %iowait (near 0%),
>>>>> iotop confirms very little IO (<5 K/s), typical data
>>>>> Device:         rrqm/s   wrqm/s     r/s     w/s   rsec/s   wsec/s
>>>>> avgrq-sz avgqu-sz   await  svctm  %util
>>>>> sdb1              0.00   231.00    0.00  156.33     0.00 79194.67
>>>>> 506.58 0.46    2.94   1.49  23.37
>>>>>
>>>>> Something is throttling this IO as 40M/s is about half of what I was
>>>>> hoping for. Will dig some more.
>>>>>
>>>>> -Henk
>>>>>
>>>>> ________________________________________
>>>>> From: drbd-user-bounces at lists.linbit.com
>>>>> [drbd-user-bounces at lists.linbit.com] on behalf of Philipp Reisner
>>>>> [philipp.reisner at linbit.com]
>>>>> Sent: Thursday, October 23, 2014 9:17 AM
>>>>> To: drbd-user at lists.linbit.com
>>>>> Subject: Re: [DRBD-user] drbd storage size
>>>>>
>>>>> Am Donnerstag, 23. Oktober 2014, 08:55:03 schrieb Digimer:
>>>>>> On 23/10/14 04:00 AM, Philipp Reisner wrote:
>>>>>> > 2a) Initialize both backend devices to a known state.
>>>>>> >
>>>>>> >      I.e. dd if=/dev/zero of=/dev/sdb1 bs=$((1024*1024))
>>>>>> oflag=direct
>>>>>>
>>>>>> Question;
>>>>>>
>>>>>>    What I've done in the past to speed up initial sync is to create
>>>>>> the
>>>>>> DRBD device, pause-sync, then do your 'dd if=/dev/zero ...' trick to
>>>>>> /dev/drbd0. This effectively drives the resync speed to the max
>>>>>> possible
>>>>>> and ensures full sync across both nodes. Is this a sane approach?
>>>>>>
>>>>>
>>>>> Yes, sure that is a way to do it. (I have the impression that is
>>>>> something
>>>>> form the drbd-8.3 world.)
>>>>>
>>>>> I do not know from the top of the head if that will be faster than the
>>>>> built-in background resync in drbd-8.4.
>>>>>
>>>>> Best,
>>>>> Phil
>>>>>
>>>>> _______________________________________________
>>>>> drbd-user mailing list
>>>>> drbd-user at lists.linbit.com
>>>>> http://lists.linbit.com/mailman/listinfo/drbd-user
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>>>>> drbd-user mailing list
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>>>>>
>>>>
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>>
> 




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