Home » SAN de bajo coste

SAN de bajo coste

En tiempos de crisis describimos los puntos clave para  diseñar una SAN de bajo coste.

  • iSCSI

iSCSI   es una alternativa a la clásica SAN de fibra óptica, siendo económica su implementación ya  que no requiere de una infraestructura y tecnología adiccional Hardware de costosas HBAs y Switches de Fibra. Con sólo un switch ethernet ( o dos que aporten redundancia de acceso) y  con un servidor con tarjetas Ethernet de Gigabit junto con unos discos ya tendrías una SAN. Los initiators y targets  iSCSI en muchos sistemas vienen con la distribución, al igual que las soluciones de multicamino (multipath).

Existen otras alternativas a iSCSI también basadas en Ethernet como AoE (ATA over Ethernet) que al eliminar una capa de encapsulación de frames (IP) da mayor rendimiento.

  • DISCOS

En la actualidad se diponen discos de buen precio y alta capacidad para una solución de bajo TIER. Un ejemplo podría ser 4 discos SATA de 3Gb/s ,  capacidad 2 TB,  64 MB de Caché y 7200 rpm  con un total aproximado de 500€. Proporcionando aproximadamente unos 6 TB en RAID software con MDADM (solución de servidores Linux de RAID software) , que nos da una media de 111 euros por Tera tolerante a fallo (RAID).

Preguntadle a vuestro proveedor de SAN cuanto saldría una amplación de los TB en fibra …   😉

Aunque no es comparable una cabina de discos en fibra en cuanto a rendimiento debido a sus fenomenales características Hardware (tarjetas de fibra operando en modo target y procesadores dedicados, memoria caché del frontend y backend de los discos, …). Además sus discos tienen un rendimiento mayor,  15.000 rpm frente a los 7200 rpm que tienen  los discos SATA, comparativamente  pueden  duplicar las I/Os y mejoras como gestión de colas o DIF T10. Según la necesidad de las aplicaciones del uso intensivo de disco podría ser adecuada una solución de bajo TIER.

  • RAID

La tecnología RAID Hardware dejó de ser hace años exclusiva de entornos enterprise y cualquier placa de PC lleva integrado una controladora de discos SATA con soporte de RAID 0,1,5.  Por otro lado los resultados del RAID por software (MDADM, ZFS, …) y los gestores de volúmenes (Logical Volumen Manager – LVM ,Solaris Volumen Manager – SVM ,Veritas Volume Manager – VxVM, ZFS, …) demuestran ser alternativa eficaz que  complementan de forma segura y hacen flexible cualquier cambio posterior en el almacenamiento.

  • MULTIPATH

Una solución SAN en iSCSI necesitaría de un switch ethernet para conectar los Initiator/s con los Target/s. Un diseño en SAN de fibra típico sería redundar HBAs y Switches de fibra proporcionando multicamino (multipah) al sistema eliminando puntos de fallo, se conseguiría de esta forma prevenir de cualquier fallo Hardware la continuidad de acceso a los discos. Esta tolerancia a fallos también es posible realizarse por analogía en iSCSI, redundando tarjetas  y switches ethernet, acompañado de un software multipath propio de la distribución o usando nativamente el multipath iSCSI.

  • SAN/NAS

Cualquier sistema UNIX/Linux dispone de soporte para protocolos fibra e iSCSI y combinar con  cualquier protocolo de compartición de ficheros como SMB o NFS. Ésto nos permitiría crear un servidor que centraliza el almacenamiento en el CPD redireccionándolo a ethernet sobre protocolos de bloques (iSCSI) o de ficheros (SMB,NFS).

También existen soluciones enterprise con esta funcionalidad  basadas en software abierto tales como NexentaStor,  OpenFiler o FreeNAS.

  • Sistemas de Ficheros con reservas

El acceso de diferentes servidores a los mismos volúmes (típico en clústeres) necesitan tener un control de acceso y reservas de forma que haya coherencia en las modificaciones en el sistema de ficheros. Ésto se puede conseguir eligiendo un sistema de ficheros de tipo disco compartido (Share Disk File System)   como GFS (REDHAT) o VMFS (VMWARE).

  • Controladoras Activo/Activo Activo/Pasivo

Soluciones software tipo  IET en servidores linux  sobre las tarjetas ethernet del servidor  como Enterprise Target iSCSI proporcionará un comportamiento  análogo al  típico de  las controladoras de cabinas de discos  en fibra.

  • Soporte

El tema más delicado ya que el soporte SAN va en función de la interoperabilidad entre fabricantes destacando los elementos siguientes:

Sistema Operativo – Multipath – HBA-Drivers – Switch – Almacenamiento – Modos del multipath

Y debido a que el diseño de cada elemento en su totalidad  no se ajusta a los mismos estándares se necesita una certificación previa entre diferentes fabricantes.

Esta situación cambia bastante en un entorno iSCSI siendo un protocolo/estandar bien definido con una implementación precisa, que crea un marco de interoperatibidad mucho mayor.

Aún así, hablamos  de la infrestructura que contiene los datos de una empresa, y si algo en su CPD debe de tener soporte es este almacén de datos. Por lo que el final de este diseño propuesto puede variar bastante si no se quiere contratar soporte … incluyento por ejemplo  soluciones de backup, Alta disponibilidad (HA) con replicación síncrona entre dos cabinas de discos, … todo un tema a desarrollar y cuya implementación en producción es aconsejable que deba superar toda una fase de testeo intensivo  y planes robustos de contingencia.

Lo aconsejable es buscar soporte en alguna solución tipo Openfiler, siendo una de las soluciones más flexibles que cumple los puntos propuestod … aunque no olvidar que hay que mirar la interoperabilidad con lupa y como ejemplo  VMWARE no la certifica para sus servidores ESX.

Por otro lado si se elige una implementación  de un target iSCSI sobre un sistema operativo, ésta solución  no tiene porqué dejar de ser soportada por la distribución, ejemplo de ellos son: RHEL que incluye desde la versión 5.3 soporte para esta característica integrando SCSI Target Framework proyecto integrado en la linea principal de desarrollo del Kernel y mantenido por el creador de IET u OpenSolaris/Solaris Express 11 con el proyecto COMSTAR.

En Almacenamiento Abierto hemos diseñado cabinas de discos para entornos de producción con las siguientes características:

Ubuntu Server / SCST / LVM2 / MDADM (RAID 5) / HOT SPARE / ESX/ESXi 4/ MULTIPATH Nativo iSCSI/ SATA

Su aplicación para entornos de producción es un punto de interés fuerte por eso le hemos dedicado una serie de artículos sobre el proyecto SCST.

Si estás interesado en una implementación de targets SCST de bajo Tier certificado para VMWARE u otro entorno quizás te podamos ayudar, o si ya has implementado una o estás en en el proceso, nos gustaría conocer tu experiencia.

One Response to “SAN de bajo coste”

  1. This is the right website for anybody who really wants to
    understand this topic. You realize so much
    its almost tough to argue with you (not that I really will need to…HaHa).
    You certainly put a brand new spin on a subject which has been written about for years.
    Excellent stuff, just excellent!

  2. It’s actually a cool and helpful piece of information. I am glad that you shared
    this useful information with us. Please stay us informed like this.
    Thanks for sharing.

  3. When I initially commented I clicked the «Notify me when new comments are added» checkbox and now each time a comment
    is added I get three e-mails with the same comment.

    Is there any way you can remove people from that service?
    Thanks a lot!

  4. Hello are using WordPress for your blog platform?
    I’m new to the blog world but I’m trying to get started and create my own.
    Do you require any html coding expertise to make your own blog?
    Any help would be really appreciated!

  5. pi0cket.com dice:

    My spouse and I stumbled over here coming from a different web page and thought I might as well check things out.
    I like what I see so i am just following you.
    Look forward to exploring your web page again.

  6. I want to to thank you for this great read!! I absolutely
    loved every little bit of it. I have you book-marked to look at
    new things you post…

  7. Hey! I know this is kinda off topic but I was wondering which blog platform are
    you using for this site? I’m getting fed up of
    Wordpress because I’ve had issues with hackers and I’m looking at alternatives for another platform.
    I would be great if you could point me in the direction of a good
    platform.

  8. Excellent post. I was checking continuously this blog and I’m impressed!
    Extremely useful info particularly the last part 🙂 I care for such information much.
    I was looking for this particular information for a long time.

    Thank you and best of luck.

  9. Your mode of describing all in this post is in fact fastidious,
    every one be capable of easily understand it, Thanks a lot.

  10. Interesting blog! Is your theme custom made or did you download it from somewhere?
    A theme like yours with a few simple tweeks would really make my blog
    stand out. Please let me know where you got your design. With thanks

  11. Hey there are using WordPress for your site platform? I’m new
    to the blog world but I’m trying to get started and set up my own. Do you require any html coding
    expertise to make your own blog? Any help would be really appreciated!

  12. What’s up to all, the contents existing at this website are genuinely
    awesome for people experience, well, keep up the nice work fellows.

  13. Very energetic article, I liked that a lot. Will there
    be a part 2?

  14. I don’t know whether it’s just me or if perhaps everyone else encountering problems with your blog.
    It appears like some of the written text within your posts are running off the
    screen. Can someone else please provide feedback and let me know if
    this is happening to them too? This could be a issue with my web browser because I’ve had this happen previously.
    Appreciate it

  15. It’s actually a great and useful piece of
    information. I am satisfied that you just shared this helpful info
    with us. Please keep us up to date like this.
    Thank you for sharing.

  16. Wow that was strange. I just wrote an incredibly long comment but after I clicked submit my comment didn’t
    appear. Grrrr… well I’m not writing all that over again. Anyhow, just wanted to say fantastic blog!

  17. Hey there! Would you mind if I share your blog with my facebook group?
    There’s a lot of folks that I think would really enjoy your content.
    Please let me know. Thanks

  18. I’m gone to convey my little brother, that he should also pay a quick visit this weblog on regular basis to get updated from newest news update.

  19. Piece of writing writing is also a excitement, if you know
    after that you can write if not it is difficult to write.

  20. Hi, after reading this remarkable paragraph i am too delighted to share my know-how here with colleagues.

  21. cults3d.com dice:

    Hello there, I discovered your blog via Google at the same
    time as looking for a comparable matter, your website came up, it appears to
    be like good. I’ve bookmarked it in my google bookmarks.

    Hello there, simply turned into aware of your blog thru
    Google, and found that it’s truly informative.

    I’m going to be careful for brussels. I will appreciate when you continue this in future.
    A lot of other folks will probably be benefited from your writing.
    Cheers!

  22. Hi! This is kind of off topic but I need some advice from an established blog.
    Is it very hard to set up your own blog? I’m not very
    techincal but I can figure things out pretty fast.
    I’m thinking about making my own but I’m not sure where to start.
    Do you have any ideas or suggestions? With thanks

  23. Truly no matter if someone doesn’t know afterward its up to other viewers that they will assist,
    so here it happens.

  24. This paragraph offers clear idea for the new users of blogging,
    that truly how to do blogging and site-building.

  25. Ahaa, its fastidious discussion about this paragraph at this place
    at this webpage, I have read all that, so at this time me also commenting here.

  26. bysee3.com dice:

    Everyone loves what you guys tend to be up too. This kind of
    clever work and exposure! Keep up the excellent works guys I’ve added you
    guys to my personal blogroll.

  27. 831.one dice:

    I read this piece of writing completely on the topic of the resemblance
    of most up-to-date and earlier technologies,
    it’s awesome article.

  28. Thanks for the auspicious writeup. It in fact was a enjoyment account it.
    Look advanced to far added agreeable from you! However, how
    can we communicate?

  29. notes.io dice:

    Heya i am for the first time here. I found this board and
    I find It truly useful & it helped me out a lot. I hope to give something back and aid others like you aided me.

  30. What’s up to all, the contents existing at this site are actually awesome for people experience, well,
    keep up the good work fellows.

  31. Wow that was unusual. I just wrote an really long comment but after I clicked
    submit my comment didn’t appear. Grrrr… well I’m not writing all that over again. Anyhow, just wanted to say great blog!

  32. Asking questions are in fact pleasant thing
    if you are not understanding something entirely, but this paragraph presents nice understanding even.

  33. Hello There. I found your weblog the usage of msn. This is a very
    smartly written article. I’ll make sure to bookmark it and
    return to read more of your useful info. Thanks for the post.
    I will certainly comeback.

  34. What a stuff of un-ambiguity and preserveness of precious knowledge regarding
    unexpected feelings.

  35. Excellent post! We will be linking to this particularly
    great post on our website. Keep up the great writing.

  36. I seriously love your site.. Pleasant colors & theme. Did you develop this site yourself?
    Please reply back as I’m trying to create my own personal
    blog and want to find out where you got this from or exactly what
    the theme is named. Thanks!

  37. My brother recommended I would possibly like this web site.
    He was entirely right. This submit actually made my day.
    You can not imagine just how so much time I had spent for this info!

    Thanks!

  38. This piece of writing will assist the internet people for
    building up new webpage or even a blog from start to end.

  39. If you want to increase your experience simply keep visiting this web page and
    be updated with the newest news update posted here.

  40. Whats up very nice site!! Guy .. Beautiful .. Wonderful ..
    I will bookmark your blog and take the feeds also?
    I am satisfied to find a lot of useful information right
    here within the post, we want work out extra strategies in this regard, thanks for sharing.
    . . . . .

  41. I was suggested this blog by my cousin. I’m not sure whether this post is written by him as no
    one else know such detailed about my difficulty. You are wonderful!

    Thanks!

  42. Undeniably consider that that you stated.
    Your favorite justification appeared to be on the internet
    the easiest factor to be mindful of. I say to you, I certainly get irked at the same time as other folks think about issues that they
    just don’t recognise about. You managed to hit the nail upon the highest and also outlined out the entire
    thing with no need side-effects , folks can take a signal.
    Will likely be back to get more. Thanks

  43. These are truly fantastic ideas in on the topic of blogging.

    You have touched some good factors here. Any way keep up wrinting.

  44. onlines.pro dice:

    Incredible points. Outstanding arguments. Keep up the amazing effort.

  45. Alejandro dice:

    Spot on with this write-up, I honestly feel this web site needs a lot more
    attention. I’ll probably be back again to read more, thanks for
    the info!

  46. Willis dice:

    Greetings! Very useful advice in this particular post!
    It is the little changes that make the largest changes.
    Many thanks for sharing!

  47. Tabitha dice:

    Wow that was unusual. I just wrote an really long comment but after I
    clicked submit my comment didn’t appear. Grrrr…
    well I’m not writing all that over again. Anyways, just wanted to say excellent blog!

  48. Vince dice:

    I’m gone to tell my little brother, that he should
    also go to see this webpage on regular basis to get updated from most up-to-date news update.

  49. […] con el artículo anterior que describía tecnologías para la implementación de un SAN de bajo coste, añado una interesante […]

Deja una respuesta

Tu dirección de correo electrónico no será publicada. Los campos obligatorios están marcados con *