similar to: Possible to use multiple disk to bypass I/O wait?

Is it possible or will there be any problems with using mdraid on top of mdraid? specifically say mdraid 1/5 on top of mdraid multipath. e.g. 4 storage machines exporting iSCSI targets via two different physical network switches then use multipath to create md block devices then use mdraid on these md block devices The purpose being the storage array surviving a physical network switch

I was trying to do some performance testing between using iSCSI on the host as a diskfile to a guest vs the VM guest using the iSCSI device directly. However, in the process of trying to establish a baseline performance figure, I started increasing the MTU settings on the PCI-express NICs with RTL8168B chips. First bottleneck was discovering the max MTU allowed on these is 7K instead of 9K but

Might be slightly OT as it isn't necessarily a CentOS related issue. I've been using WD Reds as mdraid components which worked pretty well for non-IOPS intensive workloads. However, the latest C7 server I built, ran into problems with them on on a Intel C236 board (SuperMicro X11SSH) with tons of "ata bus error write fpdma queued". Googling on it threw up old suggestions to

Has anybody tried or knows if it is possible to create a MD RAID1 device using networked iSCSI devices like those created using OpenFiler? The idea I'm thinking of here is to use two OpenFiler servers with physical drives in RAID 1, to create iSCSI virtual devices and run CentOS guest VMs off the MD RAID 1 device. Since theoretically, this setup would survive both a single physical drive

On 4/13/11, Rudi Ahlers <Rudi at softdux.com> wrote: >> to expand the array :) > > I haven't had problems doing it this way yet. I finally figured out my mistake creating the raid devices and got a working RAID 0 on two RAID 1 arrays. But I wasn't able to add another RAID 1 component to the array with the error mdadm: add new device failed for /dev/md/mdr1_3 as 2:

I've been trying to do traffic shaping on one of my public servers and after reading up, it seems like the way to do so is via tc/htb. However, most of the documentation seems at least half a decade old with nothing new recently. Furthermore, trying to get documentation on tc filters turned up a blank. man tc refers to a tc-filters (8) but trying to man that gives a no such page/section

I've been reading that it's possible to set up a system with multiple NIC to provide redundant internet connectivity such that it will switch to a secondary connection if the primary ISP fails. Is it possible in a similar way to setup redundant LAN routing? I read that it is possible to aggregate/bond multiple NIC to stackable switches that support link aggregation and redundancy. But if

On Tue, Feb 10, 2015 at 1:54 PM, Chris Murphy <lists at colorremedies.com> wrote: > > - I would not put swap on an md device, I'd just put a plain swap > partition on each device; first create two swap mountpoints, If one of the devices fails, doesn't that mean that any processes with swap on the associated space will be killed? Avoiding that is kind of the point of

I'm trying to figure out what's causing an average system load of 3+ to 5+ on an Intel quad core. The server has with 2 KVM guests (assigned 1 core and 2 cores) that's lightly loaded (0.1~0.4) each. Both guest/host are running 64bit CentOS 5.6 Originally I suspected maybe it's i/o but on checking, there is very little i/o wait % as well. Plenty of free disk space available on all

In a moment of epic stupidity, having ran out of space on the root partition of a server due to /var chewing up the space, I added a separate drive for the purpose of mounting it as /var To do so, I mounted the new drive as /var2, cp -R (in hindsight should had rsync to preserve attributes), deleted the original /var to free up space, edited fstab and rebooted... unsurprisingly to a fubar'd

I was having problems with the same server locking up to the point I can't even get in via SSH. I've already used HTB/TC to reserve bandwidth for my SSH port but the problem now isn't an attack on the bandwidth. So I'm trying to figure out if there's a way to ensure that SSH is given cpu and i/o priority. However, so far reading seems to imply that it's probably not going

Hello I get the following error on the server. The problem is resolved when you restart. But is this causing the problem? messages_log: INFO: task jbd2/dm-1-8:674 blocked for more than 120 seconds echo 0 > /proc/sys/kernel/hung_task_timeout_secs Thanks.

I'm trying to improve the setup of our Dovecot/Exim mail servers to handle the increasingly huge accounts (everybody thinks it's like infinitely growing storage like gmail and stores everything forever in their email accounts) by changing from Maildir to mdbox, and to take advantage of offloading older emails to alternative networked storage nodes. The question now is whether having a

> Please check if there is also error log contained OOM kill? It does not appear. On Wed, Dec 7, 2016 at 4:41 PM, -=X.L.O.R.D=- <xlord.sl at gmail.com> wrote: > Dear, > Please check if there is also error log contained OOM kill? > > Xlord > > -----Original Message----- > From: CentOS-virt [mailto:centos-virt-bounces at centos.org] On Behalf Of Gokan > Atmaca >

I'm trying to setup a very small system intended for doing monitoring/logging. It's done on an Intel Atoms in a small box and the idea was to simply run it off a pair of USB flash drives in software RAID 1. Now the problem is that while the 6.2 DVD installer could go through the entire install process, grub will load then just stop at the prompt. The system will work if I use a SATA hard

Which of these would be the recommended virtualization platform for mainly CentOS guest on CentOS host for running a virtualized mail server? From what I've read, objectively it seems that VMWare's still the way to go although I would had like to go with Xen or KVM just as a matter of subjective preference. VMWare's offering seems to have the best support and tools, plus likely the

After successfully getting higher MTU to work on my Realtek NICs, I started testing the impact of higher MTU on file transfers using NFS exported ramdisk to ramdisk. The results were unexpected. The higher the MTU on the sending NIC, the lower the file transfer speed. I tested by using time cp to copy a 1GB file (In case compression might affect the results, so I dd the test file from the CentOS

I am a developer from the 'Frugalware Linux' distribution. I have been trying to use the syslinux lua module to support more dynamic menu generation at runtime for our distributed ISO images, as Grub2 is not very configurable for this. For example, I need raw access to the PCI bus information to configure the video output kernel boot parameters for specific hardware. Specifically,

PJ wrote: > This may or may not be CentOS related, but am out of ideas at this point and wanted to bounce this off the list. > > I'm running a CentOS 5.5 server, running the latest kernel > 2.6.18-194.32.1.el5. > > Almost everyday around 3:30 AM the server completely locks up and has to be power cycled before it will come back online. > (this means someone hat to wake up

Can I combine VMWare ESXi (free version) virtualization and CentOS mdraid level 1? Any pointers how to do it? I never used VMWare before. - Jussi -- Jussi Hirvi * Green Spot Topeliuksenkatu 15 C * 00250 Helsinki * Finland Tel. +358 9 493 981 * Mobile +358 40 771 2098 (only sms) jussi.hirvi at greenspot.fi * http://www.greenspot.fi