25 votes

Disable hyperthreading from within Linux (no access to BIOS)

Newer Kernels provide a Simultaneous Multithreading (SMT) control. You can check the state of SMT with; cat /sys/devices/system/cpu/smt/active Change the state with echo off > /sys/devices/...
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17 votes

replacing 3 drives out of 8 in a server

Why would you ask the internet about this? There's so much WTF here, that I don't understand where to start!! This question shows a fundamental lack of understanding of hardware, RAID arrays, ...
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  • 194k
16 votes
Accepted

iDRAC login loop

Have you tried looking at the iDRAC6 troubleshooting guide? They have a whole section of things to try for logon loops Continual Loop (Normally noticed when customer is trying to log into GUI ...
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  • 7,795
14 votes

Disable hyperthreading from within Linux (no access to BIOS)

A script to disable hyperthreading in the machine startup... To disable hyperthreading I include a script on machine /etc/rc.local. It is not exaclty clean, but is easy to install, independent of cpu ...
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  • 513
14 votes

How do I stop Dell R730xd fans from going full speed when Broadcom/QLogic NetXtreme 57711 PCI card added?

After tearing my hair out on newly arrived lovely R730xd with 16 3.5" disk slots spinning fans at 15k RPM when Intel X520-DA2 10G card is in any PCI slot, I've found following solution for CentOS 6.7 ...
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  • 413
13 votes

Purpose of vent holes on the top of rackmount servers?

(Some people are hard to please...) These are likely system exhaust vents and fit into the total design of the product. Please understand that the system is designed and optimized for rack mounting ...
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  • 194k
11 votes

Dell PowerEdge: powersaving BIOS settings differences

The following Dell Whitepaper goes in depth on the differences between the different power profiles: http://en.community.dell.com/techcenter/extras/m/white_papers/20248740 (page 20-36) Below you can ...
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  • 275
11 votes

How to install ZFS on Dell Poweredge server and Dell disk array without using the RAID controller

It depends: H200/300 and PERC9 (ie: 330, 730, 830) cards have the capability to work in pass-through mode, meaning that the disks can be directly presented to the operating system. To do that, you ...
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  • 43.1k
11 votes
Accepted

Can we upgrade Dell's basic Server R240 (which still uses HDD 7200RPM) to an SSD?

On Dell's R210, R220 and T130 I've successfully used Sandisk's consumer grade SSDs for years. I've done this with PERC's H410 and H710 controllers. It will be a matter of controller and controller's ...
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  • 1,679
10 votes

Disable hyperthreading from within Linux (no access to BIOS)

You can use the "thread_siblings_list" for each core to turn off the second core in the HT pair. The following command pipeline is hacky, not optimised, and done this way hopefully to make it easier ...
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  • 533
10 votes

replacing 3 drives out of 8 in a server

With RAID 5 you can only lose 1 disk and have your data remain available. You have lost 3 so you will need to rebuild the RAID and then restore the data from backup. We have a canonical Q&A about ...
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  • 113k
9 votes
Accepted

Trouble Installing Windows Server 2008 on Dell PowerEdge R720 w/ PERC H710 Mini

You should be using the LifeCycle Controller to install the OS, which will include the appropriate drivers for your RAID controller.
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  • 107k
9 votes

Can we upgrade Dell's basic Server R240 (which still uses HDD 7200RPM) to an SSD?

Yes, you can swap HDDs <-> SSDs the way you want. Moreover, it's OK to use non-Dell branded SSDs inside Dell servers, you won't receive support (of course!) and some functions won't work like LEDs, ...
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8 votes
Accepted

Dell 1950: How to tell what generation it is?

Visual Indicator on the Chasis If you don't have a circle with a II or III then it's a I: credit - Dell community forum
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  • 2,683
8 votes

Infrequent input/output error - Linux server

You have one drive in a RAID that is misbehaving, and producing occasional errors? Sounds like a hardware problem, and one that is likely to get worse. You should consider replacing the drive. Yes, it'...
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8 votes
Accepted

Max drive size for PERC H700 in Dell r610

Just to share my config, i got a PERC H700 (inside a R410 server) with the firmware version 12.3.0-0032 and my 4 new hard drives IronWolf 10 TB are seen as 2 TB drives. After upgrading the firmware to ...
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  • 1,679
8 votes
Accepted

Dell PowerEdge T310 won't POST after memory upgrade

Take a look at the technical data sheet for your memory. Specifically, the HMT31GR7BFR4A you have is dual-rank, not quad-rank. Your system probably does not support dual-ranked 8 GB for 32 GB total (...
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  • 1,516
8 votes

Differences between HW RAID and ZFS

Hardware RAID vs ZFS doesn't make a lot of difference from a raw throughput perspective -- either system needs to distribute data across multiple disks, and that requires running a few bit shifting ...
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7 votes

Reset DELL iDRAC password without rebooting ESXi

Try this from the command line: racadm racresetcfg If you have the DRAC tools installed, it'll reset your DRAC to factory defaults. If it fails, you're stuck rebooting the server.
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  • 14.8k
7 votes

Dell PowerEdge R200 won't boot, has flashing green and blue lights

Well, right up front, let me tell that the outlook is not good. 10:1 (at least) that your motherboard is bad and needs to be replaced. The standard troubleshooting approach to this problem is to ...
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  • 53.2k
7 votes
Accepted

control a server before the OS loads

Your server should have DRAC available and there are most likely upgrade licenses available to allow full remote management capabilities (including remote video that works completely without OS). DRAC ...
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  • 96.4k
7 votes
Accepted

E3-1240 v5 cpufreq-info says: "no or unknown cpufreq driver is active on this CPU"

Modern Intel processors use P-states for CPU frequency control. When Linux is using this driver, it will be visible thus: # cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver intel_pstate The ...
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7 votes
Accepted

Upgrading existing environment to vSphere 6.5

1) Backup everything with Veeam 2) Decomission one host from your ESXi 5.0 cluster 3) Create one-node ESXi 6.5 cluster from decommissioned in (2) host 4) Restore VMs from your backup to your new ...
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7 votes

Dell PowerEdge T310 won't POST after memory upgrade

Diagnostic lights 1 and 4 means system board failure. Either you have the incorrect RAM, A bad ram stick or a bad system board. I looked at the firmware updates and none address an issue with ram.
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  • 1,165
6 votes
Accepted

iDRAC on Dell R710 and R720

The Express version of iDRAC 7 comes standard on the R720, with an optional upgrade for the Enterprise version.
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  • 53.2k
6 votes
Accepted

DELL PowerEdge 2950 stuck on BIOS

Make sure to unplug any USB/external drives. They can cause the server to hang at boot in many instances.
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6 votes

Samsung 840 Pro SSDs in a Dell R720

I wouldn't use consumer SSD drives. While they will work, I think the better approach is to find a cost-effective SAS (not SATA) SSD. The Dell OEM drives are Sandisk Lightning (expensive, perform OK, ...
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  • 194k
6 votes
Accepted

Samsung 840 Pro SSDs in a Dell R720

Bottom Line - You get what you pay for. Without going into a rediculous amount of detail, because I'll let the internet do it for me. There is a huge difference between an Enterprise SSD like the ...
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6 votes
Accepted

Quieting down a Dell PowerEdge r710

This is an enterprise-class server. It's doing what it was designed to do... You're using it in a manner in which it was not intended... I wouldn't recommend altering the hot-swap fans or power supply ...
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  • 194k
6 votes
Accepted

ZFS on enterprise RAID pass-through, and ZFS on FreeBSD root

You can control the PERC H730 and H330 using the LSI MegaCLI utility as both of these cards are Dell PERC badged LSI cards. There is an excellent article and tutorial on how to do this at https://...
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  • 6,583

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