>>> On Sat, 23 Feb 2008 21:40:08 +0100, Nagilum
>>> <[EMAIL PROTECTED]> said:
[ ... ]
>> * Doing unaligned writes on a 13+1 or 12+2 is catastrophically
>> slow because of the RMW cycle. This is of course independent
>> of how one got to the something like 13+1 or a 12+2.
nagilum> Changing a sing
[ ... ]
>> * Suppose you have a 2+1 array which is full. Now you add a
>> disk and that means that almost all free space is on a single
>> disk. The MD subsystem has two options as to where to add
>> that lump of space, consider why neither is very pleasant.
> No, only one, at the end of the md d
>> This might be related to raid chunk positioning with respect
>> to LVM chunk positioning. If they interfere there indeed may
>> be some performance drop. Best to make sure that those chunks
>> are aligned together.
> Interesting. I'm seeing a 20% performance drop too, with default
> RAID and LV
>>> On Tue, 19 Feb 2008 14:25:28 -0500, "Norman Elton"
>>> <[EMAIL PROTECTED]> said:
[ ... ]
normelton> The box presents 48 drives, split across 6 SATA
normelton> controllers. So disks sda-sdh are on one controller,
normelton> etc. In our configuration, I run a RAID5 MD array for
normelton> each
>> What sort of tools are you using to get these benchmarks, and can I
>> used them for ext3?
The only simple tools that I found that gives semi-reasonable
numbers avoiding most of the many pitfalls of storage speed
testing (almost all storage benchmarks I see are largely
meaningless) are recent v
>>> On Sun, 17 Feb 2008 07:45:26 -0700, "Conway S. Smith"
>>> <[EMAIL PROTECTED]> said:
[ ... ]
beolach> Which part isn't wise? Starting w/ a few drives w/ the
beolach> intention of growing; or ending w/ a large array (IOW,
beolach> are 14 drives more than I should put in 1 array & expect
beolach
>>> On Sat, 16 Feb 2008 20:58:07 -0700, Beolach
>>> <[EMAIL PROTECTED]> said:
beolach> [ ... ] start w/ 3 drives in RAID5, and add drives as I
beolach> run low on free space, eventually to a total of 14
beolach> drives (the max the case can fit).
Like for for so many other posts to this list, all
>>> On Sun, 27 Jan 2008 20:33:45 +0100, Keld Jørn Simonsen
>>> <[EMAIL PROTECTED]> said:
keld> Hi I have tried to make a striping raid out of my new 4 x
keld> 1 TB SATA-2 disks. I tried raid10,f2 in several ways:
keld> 1: md0 = raid10,f2 of sda1+sdb1, md1= raid10,f2 of sdc1+sdd1, md2 = raid0
keld
>> Why does mdadm still use 64k for the default chunk size?
> Probably because this is the best balance for average file
> sizes, which are smaller than you seem to be testing with?
Well "average file sizes" relate less to chunk sizes than access
patterns do. Single threaded sequential reads with
>>> On Tue, 25 Dec 2007 19:08:15 +,
>>> [EMAIL PROTECTED] (Peter Grandi) said:
[ ... ]
>> It's the raid10,f2 *read* performance in degraded mode that is
>> strange - I get almost exactly 50% of the non-degraded mode
>> read performance. Why is that
>>> On Sun, 23 Dec 2007 08:26:55 -0600, "Jon Nelson"
>>> <[EMAIL PROTECTED]> said:
> I've found in some tests that raid10,f2 gives me the best I/O
> of any raid5 or raid10 format.
Mostly, depending on type of workload. Anyhow in general most
forms of RAID10 are cool, and handle disk losses better
[ ... on RAID1, ... RAID6 error recovery ... ]
tn> The use case for the proposed 'repair' would be occasional,
tn> low-frequency corruption, for which many sources can be
tn> imagined:
tn> Any piece of hardware has a certain failure rate, which may
tn> depend on things like age, temperature, stab
>>> On Thu, 22 Nov 2007 22:09:27 -0500, [EMAIL PROTECTED]
>>> said:
> [ ... ] a RAID 10 "personality" defined in md that can be
> implemented using mdadm. If so, is it available in 2.6.20.11,
> [ ... ]
Very good choice about 'raid10' in general. For a single layer
just use '-l raid10'. Run 'man m
>>> On Mon, 22 Oct 2007 15:33:09 -0400 (EDT), Justin Piszcz
>>> <[EMAIL PROTECTED]> said:
[ ... speed difference between PCI and PCIe RAID HAs ... ]
>> I recently built a 3 drive RAID5 using the onboard SATA
>> controllers on an MCP55 based board and get around 115MB/s
>> write and 141MB/s read.
>>> On Mon, 22 Oct 2007 10:18:59 -0700 (PDT), Peter
>>> <[EMAIL PROTECTED]> said:
[ ... ]
thenephilim13> I can understand that if a RMW happens it will
thenephilim13> effectively lower the write throughput
thenephilim13> substantially but I'm not sure entirely sure why
thenephilim13> this would h
>>> On Thu, 18 Oct 2007 16:45:20 -0700 (PDT), nefilim
>>> <[EMAIL PROTECTED]> said:
[ ... ]
> 3 x 500GB WD RE2 hard drives
> AMD Athlon XP 2400 (2.0Ghz), 1GB RAM
[ ... ]
> avg-cpu: %user %nice %system %iowait %steal %idle
>1.010.00 55.56 40.400.003.03
[ ... ]
> w
16 matches
Mail list logo
