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

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116
votes
4answers
6k views

All servers flooded by salt water, is it possible to recover data from multi-platter drives?

All of my servers are currently flooded by salt water. Is it possible for each platter in a multi-platter drive to be separated, cleaned, imaged, and merged into a new virtual drive for data ...
113
votes
2answers
19k views

What are the different widely used RAID levels and when should I consider them?

This is a Canonical Question about RAID levels. What are: the RAID levels typically used (including the RAID-Z family)? deployments are they commonly found in? benefits and pitfalls of each? ...
72
votes
8answers
8k views

How can a single disk in a hardware SATA RAID-10 array bring the entire array to a screeching halt?

Prelude: I'm a code-monkey that's increasingly taken on SysAdmin duties for my small company. My code is our product, and increasingly we provide the same app as SaaS. About 18 months ago I moved ...
52
votes
8answers
3k views

What are the advantages of tape drives?

IBM still develop and sell tape drives today. The capacity of them seems to be on a par with today's hard drives, but the search time and transfer rate are both significantly lower than that of hard ...
44
votes
8answers
59k views

How can I monitor hard disk load on linux

Is there a good command line utility to monitor hard disk load on linux? Something like top but then monitoring disk activity i.s.o. cpu usage. More specifically, I suspect that for some (heavy load) ...
44
votes
7answers
18k views

How can I successfully mount an 8-bit SCSI drive on a modern computer?

I have a number of internal 8-bit SCSI-1 drives that I'd like to archive for historical purposes. These are all the old NeXT Cubes and NeXTStations (monochrome and color) that were used by id ...
43
votes
3answers
48k views

What are the merits of SAS vs SATA drives? [closed]

What are the merits of buying SAS drives over SATA drives, or vice versa?
41
votes
23answers
7k views

How do I destroy a hard disk?

I have an old hard disk (Maxtor 250Gb) from about 3 years ago that started giving errors and now sits in a draw in my desk. It has some confidential data on it but it's unlikely that it can be read ...
37
votes
6answers
3k views

Is my Hard Drive Failing?

I just tried to run a test on my hdd and it doesn't want to complete a self test. Here is the result: smartctl --attributes --log=selftest /dev/sda smartctl 6.2 2013-07-26 r3841 ...
36
votes
10answers
3k views

Linux on VMware - why use partitioning?

When installing Linux VMs in a virtualized environment (ESXi in my case), are there any compelling reasons to partition the disks (when using ext4) rather than just adding separate disks for each ...
33
votes
11answers
12k views

Does an unplugged hard drive used for data archival deteriorate?

If I were to archive data on a hard drive, unplug it, and set it on a (not dusty, temperature-controlled) shelf somewhere, would that drive deteriorate much? How does the data retention of an ...
30
votes
10answers
12k views

How should I burn in hard drives?

Google did a very thorough study on hard drive failures which found that a significant portion of hard drives fail within the first 3 months of heavy usage. My coworkers and I are thinking we could ...
29
votes
14answers
10k views

Is it safe to store data on a hard drive for a long time?

Is it safe to backup data to a hard drive and then leave it for a number of years? Assuming the file system format can still be read, is this a safe thing to do. Or is it better to continually ...
29
votes
9answers
22k views

Reliability of ssd drives

The main advantage of SSD drives is better performance. I am interested in their reliability. Are SSD drives more reliable then normal hard drives? Some people say they must be because they have no ...
29
votes
2answers
8k views

Why are enterprise SAS disk enclosures seemingly so expensive?

I will begin by stating that I do not believe this is a duplicate of Why is business-class storage so expensive?. My question is specifically about SAS drive enclosures, and justifying their expense. ...
28
votes
9answers
6k views

To improve SQL performance, why not just put lots of RAM rather than having faster hard disks?

People keep telling me that in order to improve an SQL server's performance, buy the fastest hard disks possible with RAID 5, etc. So I was thinking, instead of spending all the money for ...
24
votes
2answers
4k views

Reliability of SSD vs HDD (Over large temperature variations)

I've got an application which requires data recording in a outdoor environment, and I am interested in the reliability of SSDs vs HDD when placed in a cold (down to -20) and hot (+50) ambient ...
23
votes
14answers
25k views

Fastest, surest way to erase a hard drive?

I'm looking for a quick, simple, and effective way to erase the hard drives of computers that my company will be getting rid of (donation to charity, most likely). Ideally, I would like a ...
23
votes
13answers
2k views

High Failure Rate of Large Drives?

I recently deployed a server with 5x 1TB drives (I won't mention their brand, but it was one of the big two). I was initially warned against getting large capacity drives, as a friend advised me that ...
23
votes
6answers
3k views

Scaling databases with cheap SSD hard drives

I hope that many of you are working with high traffic database-driven websites, and chances are that your main scalability issues are in the database. I noticed a couple of things lately: Most large ...
22
votes
4answers
2k views

Do raid controllers syncronize HDD platter rotation?

I'm in the market for a new storage solution. While researching various specs one of my coworkers said that some raid controllers can synchronize HDD rotation to the effect of all drives' sector/block ...
22
votes
8answers
1k views

How do I protect business critical data against fire?

We have 72 hard drives that contain our webcast inventory. The number is increasing. We're located in a frame building and we are afraid of not only fire, but catastrophic fire. I've priced fireproof ...
21
votes
8answers
544 views

Server vendor that allows 3rd party disks

As noted here, Dell is no longer allowing 3rd party disks to be used with their latest servers. As in, they don't work period. Which means that if you buy one of these boxes and want to upgrade the ...
20
votes
4answers
1k views

Why would a heavily disk intensive application run faster on a SAN than on a Physical Disk?

Why would a heavily disk intensive application run faster on a SAN than on a Physical Disk? I would have expected the Physical disk to be slightly faster but in fact the process ran 100 times faster ...
20
votes
4answers
2k views

SSD head / cylinder / cluster details

A customer of ours makes industrial robots that run on very old, but stable, hardware and software. The only bottleneck has always been the hard drive in these moving machines. Due to constant ...
20
votes
6answers
7k views

Is a hard drive's serial number globally unique?

On Linux I can use smartctl to get a hard drive's vendor, model, firmware revision and serial number: # smartctl -a /dev/sdb smartctl 5.40 2010-07-12 r3124 [x86_64-unknown-linux-gnu] (local build) ...
20
votes
3answers
33k views

Setting Low Disk Space Alerts on Windows Server 2008

I was wondering if there is an easy way to trigger an e-mail alert on Windows Server 2008 when any logical disk partitions become low on space. I have 2 SQL servers that have come close to running ...
20
votes
1answer
256 views

Is it possible that just one bit switches so my file shows me a letter “Q” instead of a “S”

In our application we use Hibernate and PostgreSQL to store data. In one of our database tables we have a discriminator column which says for example "TIPPSPIEL". It is a fixed string and can not be ...
19
votes
8answers
553k views

How to format as FAT32 from Windows 7/Vista

What is the best way to format a USB drive with FAT32 (for Mac compatibility) from within Windows 7/Vista? I ask because the Disk Management only lets you pick exFAT (because the disk is over 32GB I ...
19
votes
3answers
504 views

Replacing Hard Drives [closed]

I was wondering if it is a good idea to replace a hard drive in a (fairly) system-critical database server after a certain number of years of use, before it dies. For example, I was thinking of ...
18
votes
2answers
2k views

In Linux, why isn't superuser root's folder under /home?

You can create a user that has privileges like root, and it's home directory will fall under /home/username. Why does root get its own folder at the top level of the file system? Is this just ...
18
votes
2answers
4k views

RAID-6: better to replace two dead drives at the same time, or one at a time?

We have a 16-drive RAID-6 that has three problem drives. Two are already dead, and the third is giving SMART warnings. (Nevermind how it got in such a bad state.) Obviously we want to replace the ...
18
votes
3answers
15k views

limit linux background flush (dirty pages)

Background flushing in linux happens when either too much written data is pending (adjustable via /proc/sys/vm/dirty_background_ratio) or a timeout for pending writes is reached ...
18
votes
2answers
424 views

An unknown tool is wiping our Virtual Machines and we can't ID it

A console view of a Windows 2008 R2 VM, on vSphere is showing the following screen: "Operation 2 of 2" "Wiping disk" Can someone advise on what this program is? Some information on this mystery: ...
18
votes
3answers
11k views

CentOS thinks Disk is busy, can't mount or fsck

I'm a longtime user, and first time question submitter. I've spent a full day searching this and many other sites for a solution, but I must resort to requesting assistance to resolve my situation. ...
17
votes
14answers
8k views

How can I destroy data on a failed hard disk without voiding warranty?

Suppose I have a hard disk with data I don't want to expose to a third party. The warranty period for that disk still lasts. Now the disk starts malfunctioning. I can't use a disk wiping program on a ...
17
votes
6answers
11k views

Is bit rot on hard drives a real problem? What can be done about it?

A friend is talking with me about the problem of bit rot - bits on drives randomly flipping, corrupting data. Incredibly rare, but with enough time it could be a problem, and it's impossible to ...
17
votes
1answer
2k views

Why does unpartitioned Hitachi HDS5C3020 drive start consuming 50% more power 15 minutes after boot?

In a Debian 6.0.6 system there are 74 pieces of 2TB Toshiba DT01ABA200 drives. These drives are identified as Hitachi HDS5C3020BLE630 drives running firmware revision MZ4OAAB0. 64 Drives attached via ...
16
votes
6answers
6k views

What's the effect of standby (spindown) mode on modern hard drives?

I just assembled a new Linux file server with several Samsung HD103UJ 1TB hard drives and I am currently optimizing it. The question I can't find an answer to is: is it reasonable to set a spindown ...
15
votes
8answers
6k views

Zeroing SSD drives

We host VPSes for customers. Each customer VPS is given an LVM LV on a standard spindle hard disk. If the customer were to leave, we zero out this LV ensuring that their data does not leak over to ...
15
votes
4answers
67k views

Is it possible to mount/unmount a physical hard drive in Windows XP?

Is it possible to mount/unmount a physical hard drive in Windows XP? Ideally, I'd like to be able to do this from the command line so that I could have batch files to do it, ie: mount.cmd unmount.cmd ...
15
votes
2answers
13k views

How to determine the best byte size for the dd command

I know that doing a dd if=/dev/hda of=/dev/hdb does a deep hard drive copy. I've heard that people have been able to speed up the process by increasing the number of bytes that are read and written at ...
14
votes
3answers
719 views

Is S.M.A.R.T. smart to use?

A few years ago I was told to avoid S.M.A.R.T. like the plague. The reasoning was that the stress the testing puts on the drive will actually cause it to fail. Is this still the case? If not, what is ...
14
votes
4answers
1k views

How do limit disc i/o during backup?

I have a cron that basically do a simple "tar zcf" in the night. The server has: 8 Cores - Intel(R) Xeon(R) CPU E5606 @ 2.13GHz 25GB RAM Ubuntu 12.04.2 LTS Hardware RAID 1 (LSI Logic / Symbios ...
14
votes
5answers
22k views

Virtualbox booting from a real drive?

I'm about to take the plunge and install Win7 RC1 on my desktop machine. However I want to preserve access to my old HDD with XP on it. I don't really want to use full dual-boot since that would ...
14
votes
2answers
7k views

Are RDX removable disks a good replacement for LTO tape?

Over a period of three weeks, I experienced six complete failures of LTO-1 and LTO-2 tape drives at client sites. Some had failed mechanisms. Others lost the ability to write reliably. These were HP ...
13
votes
8answers
26k views

How can I find out what hard disks are attached to a Linux box?

Here's an easy question for you guys: How do I find out what hard drives are attached to a linux box? I'm hoping for a single command that can give me a nice list of all ata/scsi/etc drives. I've ...
13
votes
3answers
2k views

Economical way to get many harddrives into rack mount?

Please bear with me as being a bit of a newcomer at 19" rack-mounted equipment. I've thought a fair bit lately about the best way of getting 4x or 6x of 2.5" hard drives into my rack and are ...
13
votes
5answers
737 views

How do services with large ingest rates install enough hard disks fast enough?

Amazon, Facebook and Google must take in TBs if not PBs per day, so does that mean they have people continuously installing new hard disks and cables in new racks in the same way you might build a ...
13
votes
9answers
42k views

How much space should you leave free on a hard disk? [closed]

Is there a rule of thumb for how much space to leave free on a hard disk? I used to hear you should leave at least 5% free to avoid fragmentation. [I know the answer depends on usage (eg: video files ...