HDD Speed on KVM and Host (Node)

I

informant

Renowned Member
Jan 31, 2012
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10
83
Hi all,

we have on our Host (Node) a HDD Speed of more than 400MB/s and on a KVM only max. 40 MB/s. With or without cache om KVM, it´s the same issue. What can we do to have same Speed on KVM or more Speed, well 40 MB/s is very small?

regards
 
vgdisplay said:

Code: 
--- Volume group ---
  VG Name               pve
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  2896
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                3
  Open LV               3
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               4,55 TiB
  PE Size               4,00 MiB
  Total PE              1192168
  Alloc PE / Size       1188073 / 4,53 TiB
  Free  PE / Size       4095 / 16,00 GiB
  VG UUID               NY4bC7-EnxC-LGBZ-avAE-SeSi-ADQv-29ZLtc

PE size are only 4 MiB, it´s normal?

speed on node with command: dd if=/dev/zero of=testfile bs=1M count=1000
1048576000 Bytes (1,0 GB) kopiert, 2,65784 s, 395 MB/s on normal working day

speed on kvm-linux-server with same command: 1048576000 Bytes (1,0 GB) kopiert, 9,85362 s, 106 MB/s with 5 tests the max, other are 41MB/S 60MB/s 48 MB/s and 93MB/s

HDD of KVM is qcow2 without cache. testet same with vmdk and this 2 with and without cache. all the same result.

any ideas, please?


regards
 
hi sumsum,

following:
Code: 
cat /sys/block/sr0/queue/scheduler
noop anticipatory [deadline] cfq
 
Hi sumsum,

i have change with
Code: 
echo noop > /sys/block/sr0/queue/scheduler
and test again.

but, it´s the same issu. do you have any ideas?

regards
 
Is a HP Smart Array p400 with 512 MB Cache.
6x 1 TB HDD Seagate Enterprise in Raid 5.

regards
 
What the best RAID for KVM?

Code: 
hpacucli ctrl all show status

Smart Array P400 in Slot 0 (Embedded)
   Controller Status: OK
   Cache Status: OK
   Battery/Capacitor Status: OK

and
Code: 
hpacucli ctrl all show config detail

Smart Array P400 in Slot 0 (Embedded)
   Bus Interface: PCI
   Slot: 0
   Serial Number: PH7AMV2725
   Cache Serial Number: PA82C0H9SV7B52
   RAID 6 (ADG) Status: Enabled
   Controller Status: OK
   Hardware Revision: Rev D
   Firmware Version: 7.24
   Rebuild Priority: High
   Expand Priority: Medium
   Surface Scan Delay: 3 secs
   Surface Scan Mode: Idle
   Wait for Cache Room: Disabled
   Surface Analysis Inconsistency Notification: Disabled
   Post Prompt Timeout: 15 secs
   Cache Board Present: True
   Cache Status: OK
   Accelerator Ratio: 50% Read / 50% Write
   Drive Write Cache: Disabled
   Total Cache Size: 512 MB
   No-Battery Write Cache: Disabled
   Cache Backup Power Source: Batteries
   Battery/Capacitor Count: 1
   Battery/Capacitor Status: OK
   SATA NCQ Supported: True


On our DL785 we have a MSA Storage with RAID6 for this.
 
Shure, but RAID 0 is not secure, if crash and you have not an backup, all data are lose. what do you think about raid 50 or raid 60?

regards
 
Hi, very thanks, i wait of your response on later time. Biggest thanks and see you in next time with your results.

best regards
 
well its a P420i with SAS disks in RAID1, so its not comparable to your setting. I'll check later if I find a server with a P400 controller. well I know that P400 are not the fastest controllers :)
okay here we are :

On the host system
Code: 
root@virtualix08:/var/lib/vz# dd if=/dev/zero of=testfile bs=1M count=1000
1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 1.60614 s, 653 MB/s

on the guest system (old OS with 2.6.18 Kernel) :
Code: 
automatix2014:/home# dd if=/dev/zero of=testfile bs=1M count=1000
1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 2.8394 seconds, 369 MB/s

Controller Settings :
Code: 
Smart Array P420i in Slot 0 (Embedded)
   Bus Interface: PCI
   Slot: 0
   Serial Number: 0014380288ABD80
   Cache Serial Number: PBKUC0BRH5R10J
   RAID 6 (ADG) Status: Enabled
   Controller Status: OK
   Hardware Revision: B
   Firmware Version: 5.22
   Rebuild Priority: Medium
   Expand Priority: Medium
   Surface Scan Delay: 3 secs
   Surface Scan Mode: Idle
   Queue Depth: Automatic
   Monitor and Performance Delay: 60  min
   Elevator Sort: Enabled
   Degraded Performance Optimization: Disabled
   Inconsistency Repair Policy: Disabled
   Wait for Cache Room: Disabled
   Surface Analysis Inconsistency Notification: Disabled
   Post Prompt Timeout: 15 secs
   Cache Board Present: True
   Cache Status: OK
   [I][B]Cache Ratio: 10% Read / 90% Write[/B][/I]
   Drive Write Cache: Enabled
   Total Cache Size: 1024 MB
   Total Cache Memory Available: 816 MB
   No-Battery Write Cache: Enabled
   Cache Backup Power Source: Capacitors
   Battery/Capacitor Count: 1
   Battery/Capacitor Status: OK
   SATA NCQ Supported: True
   Spare Activation Mode: Activate on drive failure
   Controller Temperature (C): 68
   Cache Module Temperature (C): 31
   Capacitor Temperature  (C): 22
 
just found a server with raid5 and a P400, but we dont use this for hosting VM, ist's kinda "cold" storage system from HP.
Code: 
[root@obelix03 ~]# dd if=/dev/zero of=testfile bs=1M count=1000
1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 2.12097 s, 494 MB/s

I would recommend you to use a better host controller, if possible.
 
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