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2

Interesting question from a customer/end user perspective. My advice is not to use the HP DL380 G5 systems for anything today, if you can avoid it? They are unfavorable for power, performance, support and compatibility reasons. A few examples: RAM is very limited on this model. Any SATA SSD used on a Smart Array P400-era controller (2005-2008) will be ...


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Keep in mind that most all Enterprise RAID controllers still don't support SATA TRIM / SCSI UNMAP (give it another couple years and they likely will). That means you will need an SSD with built-in garbage collection. Most Dell-branded MLC SSDs today tend to be made by Intel, with a SandForce controller on the SSD to cover the garbage collection. Without ...


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My account was a trial account. It seems SSDs are only available for full accounts.


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From reading the diskstats plugin source, munin calculates the disk utilization percentage by looking at the total time spent doing IO over a given monitoring period. If the device is spending all it's time doing IO, then it's at 100% utilization. This is somewhat independent of actual IOPS and read/write speeds, as these will have a very access-pattern ...


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I have managed to resolve the problem by setting ashift=12 (4k alignment) when creating the pool.


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/dev/random generates random data by entropy collected by your system (time delays between keyboard shortcuts, network timing by measuring the packet arrivals with nanosecond precision, etc). If there is not enough entropy, this device blocks output while it collects more entropy. /dev/urandom uses aso the collected entropy, but it uses a pseudorandom ...


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The traditional method to enable quasi-direct access to the sigle disks in absence of a true passthrough feature is to create multiple single-disk RAID0 arrays (one array for each disk). Then, you can test trim functionality using an appropriate program as trimchecker


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Using /dev/urandom should make everything faster. I wouldn't wipe an SSD like that. SSD's usually have advanced wear leveling in place. Basically, instead of writing over the existing data, the drive writes over unused portions. It'll take a bit of time to properly scramble all the data. By that time, you would have already wore down an SSD, though it's only ...


47

Don't attempt to "wipe" an SSD with tools designed for spinning magnetic hard drives. You won't actually destroy all the data, and you'll just reduce the lifetime of the SSD. Instead, use an erase tool specifically designed for SSDs, which can use the drive's internal flash erase (discard) to discard all of the blocks, including the ones you can't access. ...


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The entire path the data takes from the OS to the SSD needs to support the pass trough of TRIM commands. Generally the issue is that the hardware RAID controller does not pass trough the TRIM commands. Software RAID should be able to pass trough the TRIM commands as long as you use a normal controller (LSI HBA SAS controller or something). The arguement ...


6

Hard drives do have a multitude of error correction methods in place to prevent data corruption. Hard drives are divided into sectors, from which some may become completely unwritable / unreadable or return wrong data through data corruption - let's call the first bad sector corruption and the latter silent data corruption. Bad Sector Corruption The first ...


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Well, things are a bit more complex. Modern hard drives don't just detect errors, they have some spare sectors and smart controllers that try to relocate bad sectors. That is, when you try to read some logical sector and it doesn't read at first time, the controller tries to read it several times, and sometimes it can read it after some retries; then it ...



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