Questions about hard disks' performance, issues, tips, and software.

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3
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54 views

Why is my HDD partition a character special device?

I have a bunch of old 1T disks with an mdadm array on them. They had been out of commission for awhile, but yesterday I slotted them into a server running an up to date Debian Jessie. Eventually I ...
3
votes
0answers
643 views

Setting the queue length on HP p410(i) controllers

The guys responsible for the DB performance tuning asked me to change the queue depth on the two HP p410(i) controllers of my DL380 G6 server. They want me to switch it from automatic to 64. ...
2
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0answers
810 views

Windows Server Backup [2012 R2] - Went from 100+ copies available to 1 copy available overnight

I'm using Windows Server Backup on a Windows Server 2012 R2 system that has been in production for half a year or so. The server has around 60GB used, and the backup drive is a 160GB external drive ...
2
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0answers
118 views

actual disk iops and write merging

/dev/sdb has LVM and exposes a single logical volume, dm-0. While writing to dm-0, /proc/diskstats reports: # of writes completed sdb 29646717 dm-0 131315099 # of writes merged: sdb 101668283 dm-0 ...
2
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0answers
791 views

ext4 root filesystem corruption under XenServer 6.2 DomU

We're with a problem with filesystem corruption in guest machines in a XenServer 6.2 It only happens in Linux Machines. Randomly the filesystem remounts as read-only and them corruption starts on the ...
2
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0answers
122 views

vmware thin disk usage powercli

I want to ask a question about thin provisioning. get-vm commandlet can easly give us real space used by a vm totally. Assume that you have a virtual machine which has more than one thin disk. If ...
2
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0answers
151 views

Shrinking a volume and extending another in dynamic disk

I have a test environment where I converted a disk to dynamic, shrunk a volume, and then expanded another all on the same disk. The result is that disk management in Windows Server 2008 R2 shows two ...
2
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0answers
270 views

Convert single O/S disk to RAID 1 - Ubuntu 12.04 LTS

I have a server running Ubuntu 12.04 LTS with only a single drive. There are 2 more empty hot swap bays in the chassis. I want to add a little redundancy by adding a RAID 1 to the system. The ...
2
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0answers
400 views

What might cause DIR $file to report “File not found” when DIR $dir shows the same file just fine?

I can DIR a file and it doesn't exist, but DIRing its directory, or a file in the same directory as it, works fine. Is this a hardware or software problem? If it's hardware, is it the drive or ...
2
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0answers
645 views

udisks-daemon eating up all my memory

I'm operating a little storage server on debian, over the past months I've noticed the process udisks-daemon eating up almost all available memory. Is this just really aggressive caching or a memory ...
1
vote
0answers
20 views

Discrepancy between total sectors and calculated total sectors using fdisk

I use ubuntu on vmware. With fdisk command I got this output: Disk /dev/sda: 42.9 GB, 42949672960 bytes 255 heads, 56 sectors/track, 5874 cylinders, total 83886080 sectors Units = sectors of 1 * 512 ...
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0answers
55 views

How do I interpret a very high Avg. Disk sec/Write perfmon value?

Short version: Is the perfmon screenshot shown below enough evidence to say "something is wrong with your storage system"? Long version: I am debugging a performance problem: Some SQL Server query ...
1
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0answers
67 views

Partitions not recognized when installing Kubuntu 14.04 over complex RAID setup

I have three identical HDDs. Using a ROM utility, I configured the use of 90% of each of them as a RAID 5 array, and the other 10% as a RAID 0 array. That is, each array uses some area on all three ...
1
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0answers
41 views

how to filter sar -d disk output tidily

sar -D output-I would like a suitable command to run alongside stress -hdd but this is the output which sar -D 1 10 gives. I have filtered it using both awk |'NR > 1 {printf ...
1
vote
0answers
234 views

IBM x3950M2 server, no drives detected during windows install

I have an IBM x3950M2 (72236MU) server that was running Server 2012. I decided to swap some drives around and reinstall from scratch with Server 2012r2. However I am unable to get the windows ...
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0answers
32 views

(Unexpected?) blkio controller behavior

I'm using docker 1.4.0 with lxc-1.0.6 and cgroup-lite-1.1.5 on Ubuntu 12.04. I have 3 hard disks (/dev/[sdb-sdd]) that I write to from 3 distinct containers. They have only one XFS partition, mounted ...
1
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0answers
148 views

Are /dev/disk/by-id symlinks unreliable?

I am provisioning a Nova server and Cinder volumes using a Heat template. In order to identify the Cinder volumes attached to my OpenStack server I would like to use the /dev/disk/by-id/... symlinks ...
1
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0answers
25 views

smartd rule does not work

I have an issue with smartd. I've studied its man page, and then I've set the SMART daemon to run long test of the hard disks two times a month and alert to the specified mail address in case of ...
1
vote
0answers
589 views

XenServer 6.2 Read Only and Slow Disk I/O

I virtualized a datacenter a few months back and we have a pool of 3 HP DL360 G5 servers, each with 32GB of Memory and dual Intel Xeons. Recently we have been experiencing 2 issues, the first of which ...
1
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0answers
251 views

VMware ESXi multiple I/O latency warnings

VMware ESXi 5.1.0 server showing multiple warning events: Device mpx.vmhba1:C0:T0:L0 performance has deteriorated. I/O latency increased from average value of 3913 microseconds to 530954 ...
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0answers
1k views

HP Dl360e Gen8 Not Detecting Hard Drives

I have a new HP Proliant DL360e G8 and it is not detecting the hard drives. We are using both non-hp, and official hp hard drives from an older server (DL120). Hard drives are 3.5" and they are not ...
1
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0answers
84 views

Unable to access disks in rhel 6.5

I work for a biology lab. We recently bought a new microscope that produces an enormous amount of data - it is simply not feasible to store it on a desktop. So, we bought a storage server - the idea ...
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0answers
198 views

Debian mail server's Maildir folder with too many files causing disk I/O to go on high load

I have a Debian mail server running Postfix, Courier and Maildir, with disks on EXT3 filesystem. I have noticed that when I use my webmail application (Squirrelmail, in this case). It gets some kind ...
1
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0answers
179 views

Virtual Allocation Unreasonably High

Just upgraded our pool to Xenserver 6.2 and installed a brand new host, also with Xenserver 6.2. Was excited about the new features since Xenserver was fully open-sources (over-allocate ram, ha live ...
1
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0answers
65 views

Hardware configuration for head nodes (HDDs, memory, processor, redundancy)

I'm designing a head node whose primary function is to submit jobs to the Torque/Maui scheduler and secondary function is to run test jobs. Unfortunately, most hardware selection guides for clusters ...
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0answers
167 views

best setup for fast sustained streaming (sequential?) disk writes

i am setting up a high speed/high resolution scientific image acquisition system. i need data write rates of ~1 GB/sec sustained for ~1 hour. i don't have experience with raid, but my plan is to ...
1
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0answers
29 views

WS2003 network drive gets deactivated after restart

windows server 2003 OS runs sql backups regularly and periodically i have to restart once in a while. when the restart takes place the network drive(H) becomes deactivated which i do not understand ...
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0answers
876 views

Differences between hdparm --read-sector and dd with “Current Pending Sectors”

This was originally an "answer" to How to use hdparm to fix a pending sector? I'd been getting SMART notifications for the same "Current Pending Sector" for days. The dd solutions around weren't ...
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0answers
40 views

partitioning a 2x larger disk to house zfs migration

so there are numerous sites taking about using vdevs made from disk partitions like this in order to reorder vdevs of different sizes. however, i have the following physical disks: Disk /dev/sda: ...
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0answers
227 views

Resize a RAID 5 Partition

I'm moving my VG to a RAID, i have 3 disk 600GB, the VG is in the partition /dev/sdc2 /dev/sdc1 1G type linux <-- Boot partition /dev/sdc2 599G type Linux LVM One disk have the VG and with the ...
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0answers
90 views

Rebalance pooled disks

Using mhddfs multiple drives were pooled to form a big virtual mountpoint. Now using the mlimit option unbalancing is prevented, but the drives are already in an unbalanced state. Is there a script ...
1
vote
0answers
775 views

How do I reboot over SSH, so that fsck can be run, on a read-only file system without sudo (or root)?

I have a server in a remote location, which I think is suffering disk issues and has remounted / as read-only. My Debian (Squeeze) installation does not have a root user. I have been using sudo to ...
1
vote
0answers
434 views

Cannot initialize disk in PowerShell : Initialize-Disk throws “The disk has already been initialized”

I'm trying to change the flash drive's partition style to GPT using PowerShell, but the cmdlet throws "The disk has already been initialized" (even though I've cleaned the drive): PS ...
1
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0answers
597 views

SSD Performance under Oracle

I have serious performance issues with oracle running over ssd. I have two OCZ Vertex 3 MAX IOPS drives (firmware 2.15). It runs on a INTEL C600 SATA Chipset. Windows 2008 R2. So the issue is ...
1
vote
0answers
85 views

Ubuntu 11.04: FW400 drive won't remount on reboot

Ok, still a *nix n00b, and the answer is likely staring me in the face. Please be patient. Problem FW400 external drive will not mount on system reboot. FW cable needs to be disconnected and ...
1
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0answers
945 views

mdadm raid1, [1/2] disks failed, safe to reboot?

I am seeing the following under /proc/mdstat Personalities : [raid1] md1 : active raid1 sda2[0](F) sdb2[1] 976554876 blocks super 1.1 [2/1] [_U] bitmap: 4/8 pages [16KB], 65536KB chunk md0 : active ...
1
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0answers
149 views

SAS disk performance drops a while after reboot on cent 5.5 boxes

So we have some workstations with identical hardware. The Fedora14 box has a couple weeks uptime and still get good performance. hdparm -tT /dev/sda /dev/sda: Timing cached reads: 21766 MB in ...
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0answers
733 views

renaming hard drives (sdc to sdb) on the fly

ata2: link is slow to respond, please be patient (ready=0) kernel: [2761026.198796] ata2: soft resetting link kernel: [2761031.226669] ata2.00: disabled kernel: [2761031.226720] ata2: EH complete ...
1
vote
0answers
192 views

Why would a diskless boot linux box stop seeing local hard drives?

A little background... I work on a system that uses PXE booting for the majority of the nodes. Several of these nodes have local hard drives that are used for persistent storage of data needed for ...
0
votes
0answers
27 views

Defunct Disk Drive (DDD) in IBM ServeRAID 6i, RAID5 array

My RAID 5 array is "Critical (CRT)" Status, since one of its six 146GB 10k rpm is marked as defunct. Is it possible to replace the defective disk (FRU part number 32P0731) with a similar HP disk ...
0
votes
0answers
42 views

Popped in replacement harddrive in RAID 1 configuration; Seeing I/O but the drive is not recognized by OS or RAID controller

CentOS 5.11; Dell PowerEdge R410; Dell SAS 6/iR Integrated Blades RAID Controller. Have two drives, both in a RAID 1 array. First drive failed. Pulled it out and popped in a new drive (same brand ...
0
votes
0answers
34 views

Replacing a HDD in FreeNAS

I got a message that said one of my hard drive was degraded and im trying to figure out how to check which drive it is. I did zpool status and I got this zpool status pool: BiggyD state: ...
0
votes
0answers
32 views

Mount LVM volume as external usb drive?

I'm trying to mount my old 2x500GB drives to the new server which has the same drive volume. Both have LVM structure but it's not working. root@server [/mnt/usb]# ls /dev/sd* /dev/sda /dev/sda2 ...
0
votes
0answers
18 views

SAR returns 0 await, 0 util for mdraid volume

Trying to get a picture on what is going on with the disks in our environment, I'm gathering statistics using SAR. Why does "sar -d" return "0" for the await and util for an mdraid volume? I can see ...
0
votes
0answers
46 views

MySQL slow file I/O

I got a little issue with MySQL having slow file IO. When benchmarking 1k blocks (I did them on purpose that small for worst-case) I get an hdd speed of about 2MB/s. When looking at iotop while ...
0
votes
0answers
13 views

IAAS hard disk storage transfers: Moving a GCE persistent disk to an AWS EBS disk?

Is there a way to export a Google Compute Engine persistent disk to an AWS Elastic Block Storage? Basically, they are both hard drives, so I wonder if there is a way to export one to the other. If ...
0
votes
0answers
112 views

hp proliant microserver not detecting hard drive

So, I've hit a bit of a wall with the HP Proliant Microserver N40L. I'm trying to install a new hard drive, 4 TB, but it's not being detected by the BIOS and thus, not the OS either. It just spins up, ...
0
votes
0answers
126 views

Acknowledging a warning in DELL OpenManage

We have a DELL R510 server where we replaced all the hard drives with new but non-certified 3TB disks. Now OpenManage throws a warning for every hard disk as "non-critical", since it recognizes the ...
0
votes
0answers
39 views

Hyper-V Machine harddisk full, but not so

My virtual machine is having harddisk issues, at least that is what Hyper-V says. The VM has 20 gb available and is running ubuntu 14.x server. Its current usage is 4.7 GB and hyper-v pauses it time ...
0
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0answers
90 views

Rebuilding FakeRAID RAID 5 with new disk, no partitions show up, invalid PMBR

I have a RAID 5 array with 4 2TB disks on a HP Z800. One disk failed and was swapped out for a new one. I went into BIOS Intel Storage Matrix Utility and set the Array to rebuild with the new disk. ...